1. Risk Factors

It should be noted that solicitor child molesters are equally as dangerous as contact offenders [1]. Those who solicit and those who engage in contact offenses utilized similar grooming and offense tactics. The online solicitor engages in sexually abusive and threatening behavior, thereby victimizing the online victim [2]. In addition, most child porn users and fantasy-driven solicitators appear to engage in actual sexual contact with the victims, again per selfreport of undetected offenses.

Those with previous criminal histories for child porn present with higher risk for contact sexual offenses [3]. The ability to groom suggests that the offender is comfortable with communicating with their victim and makes crossover to contact offenses highly likely, perhaps even early in the interaction with the victim [4,5,3,6-9]. The research further indicates that the production of images tends to be hands-on recording with the offender actively involved in the sexual activity [3,10]. Noncontact offenders tend to use grooming techniques to have their victim engage in sexual activity via webcam [7]. There does not appear to be any difference between online solicitation offenders and contact offenders in terms of dangerousness [1].

Solicitation offenders tended to range in age from 19-64, suggesting that older range of over 50 may not actually age-out of offending as once suspected [11]. Offenders tended to target victims within a close geographical proximity [11], which suggests their intent to meet with the victim in person and most made their sexual intentions clear immediately (approximately within first 35 minutes) [12-14,11].

The majority of offenders and victims exchanged pictures the first day [11]. This may help desensitize the victim to sexual material and activity. Most offenders appear to be contact driven versus fantasy driven [11], with over 80% initiating telephone and email contact with the victim. The online offender often chose victims who had sexual content in their profile, assessed the victim’s perceived neediness or submissiveness, focused on victims whose profiles contained the victim’s age, and when the victim had young-sounding usernames [15]. This suggests predatory behavior and strategic capabilities which are often underestimated with the solicitation offender. Many offenders are in contact with multiple victims at the same time [11]. Much of the grooming occurred to allow for contact within 3 days [16,11] whereas others take their time to develop the relationship [17,18]. This poses a concern that perhaps the majority of solicitation offenders are contact-driven versus fantasy-driven. On the other hand, perhaps the fantasy-driven offender more quickly moves to contact with the victim to address strengthened power and sexual motivations, which would make sense from a conditioning standpoint.

Internet behavior involving sexual grooming and production of child porn represent an escalation of viewing or possessing child porn because the offender is now communicating their sexual interests to others [4,3,19,20]. This may suggest a comfortability with the deviant sexual interest as well as a comfortability with engaging in contact offenses.

Child porn offenders with smaller collections of child porn (e.g., 50) represented the highest risk group for engaging in contact offenses [3,21]. This is in opposition to McCarthy [6] who found that the dual offenders had the largest child porn collection. Extreme child porn images are rarely found in the child porn offender’s collection, likely because the offender does not justify injuring the child [22].

Some have suggested that a porn collection involving child porn is a strong indicator of Pedophilia [23]. Offenders with child porn collections were more likely to demonstrate a pattern of sexual interest in children more so than contact offenders [23]. However, the presence of child porn cannot be the sole evidence to support a sexual preference for children. Some offenders have a sexual interest in children but not exclusively to children, often involving adults as well. Some of these offenders who have a stronger sexual preference for children versus adults are likely to demonstrate difficulties in their sexual relationships with adults. Some may engage in sexual contact with adults solely to access children [24]. For others, they may collect child porn out of curiosity or other nonsexual needs.

Sex offenders who reinforce their sexually deviant and nonsexual violent motivations through repeated viewing of deviant porn and child porn are at higher risk for sexual reoffense and contact offenses. This is supported by general learning theory and the concept of habituation and is supported in the literature for sexual offense behavior [25-33]. In fact, masturbating to erotica (anything that a person finds sexually arousing) that is in any way related to a deviant sexual attraction or sexual offense behavior should be banned by use and possession by the offender. The cognitive distortions (e.g., rationalizations and excuses) offenders use to maintain their deviant sexual arousal and deviant sexual behavior help maintain the problem and may serve as permission giving [34].

A small number of Internet only offenders downloaded more extreme pictures [35]. This may indicate increased impulsivity, more extreme and deviant thoughts, and may represent a progression toward contact offenses, though more research is needed.

Sexual preferences and sexual preoccupation appear to be underestimated in samples of detected offenders [36]. This is likely due to poor assessment and diagnostic procedures. Perhaps the limited information about the offender’s true sexual preference and paraphilias prevent accurate and appropriate diagnoses from being given. Some mental health and treatment professionals fail to provide all diagnoses the offender presents with and therefore an accurate picture is not available as to the breadth of the offender’s pathologies. Of course, lack of polygraph for assessment and treatment may result in having to rely on the offender’s words about their sexual preference and the degree of their sexual and psychological problems.

Most sexual offenses against children are vastly undetected and unreported [37]. This is likely due to the reliance of offender denials of having any or significantly more contact victims. Researchers and treatment professionals need to assess for all mental health diagnoses as well as utilize polygraph and sexual arousal/attraction testing protocol (e.g., plethysmography, visual reaction time). The research clearly indicates that most child porn only offenders indeed have multiple contact victims and that most contact offenders have far more victims than detected.

It has been proffered that use of child porn may help some control sexual deviance while for others facilitates acting on preexisting fantasies and urges [38]. However, viewing deviant material may stimulate existing fantasies and lower inhibition leading to contact offenses [38]. Repeated viewing of child porn and/or contact with other offenders may weaken resolve leading to contact offense [39]. Even finding child porn accidentally while searching for regular porn impacts potential for continued child porn use and perhaps to contact offenses [39]. It is not recommended that anyone that has a sexual interest in children or adolescents, or has engaged in contact behavior with a minor, continue to use child or adolescent porn. The argument that it may help quell deviant desires goes against logic, research, and learning theory. Practice makes perfect, continued use of any child porn (including adolescent porn) strengthens deviant arousal and deviant thinking.

The longer the sex offender spends in sex offender specific treatment, the more deviant fantasies they report [40]. The reason for this is unclear. Perhaps the offender becomes more aware of their fantasies while in treatment and therefore more openly acknowledges them; maybe the offender comes to believe that they are expected to have the deviant fantasies because treatment talks about and focusses on them; or maybe the fantasies are not likely to fade away.

2. Investigative Applications

1. Never underestimate the significance of nuisance sex offenses as these offenses often are part of an offenders larger deviant scheme [41].
2. Pay attention to any similarities between the nuisance offenses and actual sexual offense behavior [24].
3. Always obtain a police report and/or criminal complaint for any police contact mentioned in the criminal history check [42]. Every police contact offers some information that helps illustrate the offender’s criminal sophistication and offense behavior history. Most have years of engaging in sexual and physically violent crimes but do not get caught. Even when caught, lack of evidence may result in no further investigation or no criminal charges being brought. The police reports and criminal history of every police contact highlight the offender’s violent history and escalation or offense behavior. Imagine during an interview, questioning the suspect about their prior behavior and they are not prepared or expecting that would have been brought-up.
4. Pay attention to probation violations and any failed court orders including the use of alcohol, failing to report as directall indicating a willingness to ignore rules and to engage in potentially risky behavior. Offenders with a prior history of violation of conditional release were more likely to offend, violently and nonviolently [43].
5. Grooming strategies used by online offenders and offline (contact) offenders are very similar. These are similar strategies used by contact offenders as well, not just those online [44].
6. Offenders may spend more time establishing a relationship with male victims prior to meeting [45].
7. Many of the offenders may not have any criminal history or no criminal sexual offense history. This does not make the offender any less dangerous, it simply means they likely have never been arrested or detected in the past.
8. Of those offenders who had no prior sex offense convictions but admitted having undetected contact victims, they had the most victims [46].
9. Many of the child porn offenders with the most contact offenses went undetected at least in part to their not having a criminal history and skills at grooming [41].
10. For child porn cases, always investigate for contact offenses. Look into any contact they may have with children/minors, any position of power/authority they may have had with minors [41]. This should also include investigating the neighborhood they live in (e.g., playgrounds, churches, pools, schools) as the offender may hang around those areas watching children or engaging the children in activities. Child porn offenders with no prior sex offense convictions admitted having the most undetected victims, and their ability to remain undetected for so long requires special attention to investigate the offender’s life [46].
11. Child porn only offenders are more likely to confess to police and admit the child porn possession. They do this to lessen the chance that law enforcement would further investigate and detect that they have contact victims [7].
12. A high percentage of children sexually abused likely never report the sexual contact or may not do so until they are much older, reducing the likelihood of prosecution due to the time lapse [47].
13. Always ask victims if the offender took pictures of them. If so, find the pictures and what was used to take the pictures or videos (cell phone, camera). The sexual behavior of the child is almost always recorded by the offender for sexual gratification and may also be used to blackmail and threaten the child into continued submission and compliance and secrecy [4,45,48-50]. In addition, the offender may use threats, intimidation, blackmail, bribes, gifts, seduction, and competition to gain victim compliance and secrecy [51,52].
14. The offender may use threats, intimidation, blackmail, bribes, gifts, seduction, and competition to gain victim compliance and secrecy [51,52].
15. Child porn offenders are likely to confess to possessing child porn; this is often misleading because by accepting a plea agreement, law enforcement is not likely to investigate for the presence of contact victims [24,46]. This is especially true when the offender is very anxious to plead guilty.
16. Use of polygraphy during the investigative process yields more admissions of contact victims [53-57].
17. It is estimated that likely 62% of child porn only cases would turn out to be contact offenses if polygraph is used [46]. Again, 40- 85% of child porn only offenders self-reported having undetected contact victims [53,58,59].
18. Offenders demonstrate strategic capabilities in their assessment of potential victim, the specific grooming process, and their ability to coerce victim compliance and secrecy. This suggests predatory behavior and strategic capabilities which are often underestimated with the solicitation offender [15].
19. Most solicitation offenders are likely contact-driven versus fantasy-driven given that most fantasy-driven offenders engage in contact offenses. Some take time to establish and develop a relationship with the victim whereas others move quickly to establish offline contact with victims, but most all eventually engage in contact offending [16,60,18,17,11].
20. Listen carefull to how the offender justifies their deviant behavior (e.g., use of child porn, engaging with children whether sexual or nonsexual, how they defend any sexual contact with children). This helps to understand the offender’s rationalizations and justifications for engaging in the offense behavior.
21. Many offenders are in contact with multiple victims at the same time [11].
22. View any porn collection as a probable Practice and Premeditation process. Practice because the offender uses the porn to strengthen deviant sexual and/or aggressive fantasies and even rehearsing how to re-enact the fantasy in real-life. Premeditation because of the planning and fantasizing that occurs prior to initiating contact with the victim, especially when the themes or behaviors depicted in the porn matches the offenders’ offense behavior. In addition, pornography is often used by the offender to desensitize children and adolescents before sexually abusing them.
23. For forensic mental health I recommend that any sex offense warrants a diagnosis of a Paraphilia. While several Paraphilias are provided in DSM-5, perhaps the most important is Paraphilia- Unspecified. To pair sex, sexual behavior, sexual arousal with love, respect, excitement is understandable. To engage in a sexual offense, regardless of age of victim, the opposite must be true. To be able to maintain sexual arousal with a nonconsenting partner, an unconscious partner, an animal, or any other deviant arousal, would be nearly impossible without some degree of acceptance for use of force, coercion, or to maintain sexual arousal and/or complete a sexual act despite victim resistance, pain, suffering, humiliation, young age, etc. The offender must have some degree of acceptance for engaging in deviant sexual behavior. When using Paraphilia-Unspecified, put into parenthesis the adjective that best describes the offender’s offense behavior (which in turn gives a picture of the offender’s thoughts and cognitive distortions), for example, “forced sex”, “rape”, “sex with an unconscious person”.

3. Limitations of the Available Research

One of the most difficult and frustrating issue that interferes with the accuracy of research is that limitations are always present. In the above literature review, several limitations are present.

1. The data is based only on child porn users, contact offenders, and dual offenders who have been identified because of arrest, prosecution, and for some, involvement in sex offender specific treatment. Therefore the generalizability of the findings are limited only to those offenders who have been identified and apprehended [6].
2. Much of the data was based on the self-report of the offender. This raises serious questions about the veracity of the offender’s claim. Some child porn offenders may deny that they have engaged in contact sexual offenses with children or adults despite having done so. The opposite is also true. Some offenders may admit to behaviors that they have not actually engaged in and may do so for a variety of reasons (e.g., impression management (e.g., to appear cooperative in treatment or with prosecution); psychological problems (e.g., wanting to appear more selfassured, powerful, or dangerous than they really are). Without polygraph, the offender’s claims are just that- claims of someone who has engaged in sexually deviant and/or violent behavior who is not likely to be totally honest.
3. The follow-up period is often less than 3 years. This presents a significant problem because the offender remains at risk for violent and/or sexual reoffense for life. In addition, most recidivism studies rely on the offender’ self-report. Even if a criminal history check was made and no prior offense was detected, that may mean 1) they have not yet been caught; or 2) they did not yet reoffend or progress to contact offenses. Most of the child porn and contact offenders, like any other offender, have typically offended for years prior to being caught. It may be another 5-10 years before they offend or before they are again caught.
4. Methodolgical problems were apparent in many of the studies [2]. Several of the studies have small sample sizes, making it difficult to generalize the findings. In fact, several studies were limited to 5 offenders and others far too few to allow adequate comparisons between offender typologies. Many of the studies, though well intentioned, failed to adequately define the population studied, that is, the specific type of sex offender they were studying. Many grouped all child sexual abusers into one category, failing to differentiate the child porn only offenders from online solicitation offenders (fantasy-only) or from those who engaged in contact offenses (contact- driven) as well as failed to differentiate the situational and preferential offenders. The literature is rich with differences in motivation and cognitive distortions between these groups. It is imperative to have clear working definitions.
5. Several studies referred to groomers to include those who did not engage in the development of a relationships with the victim, which is in fact the process of grooming. Some offenders move immediately into soliciting sexual contact online or offline thereby skipping the grooming process altogether [61-63,50]. The process of grooming and the separate process of soliciation for sexual activity need to be clearly separated and defined. The grooming of the victim and the solicitation of sexual activity from the victim occur faster online than offline and can be difficult or confusing to separate [64,5].
6. Some of the research on online predators often involves victims who were undercover investigators versus actual victims [16,65,13,50]. This presents some degree of difficulty in determining how a real victim may respond. Studies have found, however, that it is the groomer (offender), not the victim or decoy, that leads the conversation [2,66,11]. However, because decoy victims do not engage in online sexual behavior (e.g., masturbation, exchanging naked photos) they may turn the offender away [67,61]. If the offender believed that the victim was of legal age, they tended to proceed with sexual contact regardless of whether the victim was a decoy. This suggests that decoys or actual victims likely react in similar ways but have limitations of what they can and cannot do. Overall, reliable data is likely to be obtained.
7. Understand the difference between child molester, pedophile, hebephilic, and ephebophilia [42]. A pedophile has a primary sexual attraction to prepubescent children (typically 12 and under). A hebephilic has a primary sexual attraction to early adolescents (approximately ages 11-14). A ephebophilic has a primary sexual attraction to late aged adolescents (approximately ages 15-19). Any of these three types of sexual abusers may engage in sexual contact with adults for primarily nonsexual needs, such as gaining access to children or for impression management (to appear “normal”) or because there are situational offenders. A child molester engages in sexual contact with children for nonsexual needs, and likely has no sexual attraction to children (a situational offender). They are primarily sexually attracted to adults and prefer to engage in sex with adults but will substitute a child sex partner when circumstances or needs arise.
8. Some of the research included both fantasy-driven and contact-driven offenders therefore confusing the two different offending groups (e.g., counting both groups as one) with little differentiation of how the two distinct groups offended or differed from each other in the research summary.

The above represent important areas of consideration when investigating sex and other violent crimes. For those who supervise the offenders on probation or parole, it is imperative to always consider the above factors and be aware of indicators of the offender reoffending. The literature and research offer support for the above risk factors.

Obtaining a copy of police reports and/or criminal complaints from prior police interaction and convictions provide a plethora of information to use to get the offender off their alibi. Imagine the look of confidence on the offender’s face disappearing when confronted about prior similar offense behavior. Offenders do not typically expect that investigators will bring-up or even be aware of prior behavior related to the court offense behavior. In addition, almost every sexual and violent offender has prior run-ins with the law, though many of the charges are often dropped due to insufficient evidence or plea agreements for lesser charges.

Competing Interests

The author declare that there is no competing interests regarding the publication of this article.