To Catch a Predator?

DNA and the Reporting Dilemma for Sexual Assault Victims

Posted Dec 15, 2019

used with permission from pixabay
Source: used with permission from pixabay

Accused serial murderer Bradley Edwards’ trial is currently underway in Claremont, Australia.  While he has pleaded not guilty to the three murders he is accused of, he has admitted two previous sexual assaults, including the rape of a teenage girl. This, of course, surprises no one; many sexually motivated serial killers were rapists before they “graduated” to serial murder. Before Joseph James DeAngelo was the Golden State Killer, he was the Eastside Rapist and is believed to have committed 45 to 50 rapes. Samuel Little had been arrested dozens of times for armed robbery as well as assault and rape before he began killing. Serial killer Anthony Sowell was a convicted rapist.   

But what does this mean?  Most murderers never kill again. In fact, because of the premeditation involved in serial murder, criminal profilers often don’t see much in common between the one-time murderer–who tends to kill in the heat of the moment–and the deliberate predator who kills over and over. Isn’t the same true for rape?  Isn’t there a vast ocean between the aggressive date who refuses to take no for an answer (or who interprets someone who is unable to say “no” as a “yes”) and the serial rapist who creeps into a stranger’s home?

Perhaps not as much as we once thought. 

A 2019 study of 12,624 college men across 49 campuses calls into question some common assumptions about date or acquaintance rape on campus, namely that it is typically a one-time result of either a miscommunication between two people or is fueled by drugs or alcohol that cloud the judgment of an otherwise good kid, who takes advantage of someone equally drugged or high. 

The authors suggest two things. One, that most college men do not take sexual advantage of another student under any circumstances.  And two, more than 87% of alcohol-involved sexual assault was committed by serial perpetrators (e.g. date or acquaintance rapes were likely to be perpetrated over and over by the same few). Even more alarming, a select few appear to carry on with their sexual assaults long after their college days were over. 

Criminal Profiling and the Problem with Serial Rapists

At the heart of criminal profiling is the assumption (and hope) that serial rapists have a signature, a distinct style and a victim preference.  Perhaps he always breaks into homes after the children leave for school and threatens his victims with a knife.  Maybe he only assaults thin, blonde women in their early twenties. And we do see these patterns; in fact, that’s often how a serial rapist is identified in the first place. 

However, it’s not that simple. Eric Beauregard, a criminologist at Simon Fraser University, has interviewed 1,200 sexual offenders. He says most perpetrators say they do hunt for a certain type of victim; rather, accessibility and availability often trump desirability.  In other words, who they would prefer to victimize and who actually is victimized may be more a matter of convenience than a reflection of some deep psychological or sexual issue. The rapist who prefers middle-aged, white brunettes may victimize teenagers, African Americans, etc. 

After a 2009 scandal over untested DNA kits that allowed serial killer Anthony Sowell to slip through the cracks, in 2011, Cleveland’s police department finally began sending off rape kits for testing.  Of the rape kits containing DNA that generated a CODIS hit, nearly one in five pointed to a serial rapist.  And, when Cleveland investigators uploaded the DNA from the acquaintance-rape kits, they were surprised by how often the results also matched DNA from unsolved stranger rapes. It turns out that the space between acquaintance rape and stranger rape is not a wall, but a door.

These findings not only highlight the challenges of putting together a criminal profile that is murky or nonexistent, but shows just how critical DNA evidence is in both in eliminating suspects and identifying serial predators. 

Delayed Reporting:  Buying Time to Find Justice?

We all know the statistics on how few rapes are actually reported to law enforcement and of the ones that are, how few are convicted. Victims are afraid of being scrutinized, questioned, disbelieved, or dismissed and many of them are. This is especially true in the 80% of rapes that involve known assailants. 

Given that the best chance of collecting accurate information and forensic evidence is within the first 24 hours of the sexual assault (although it can be collected for up to seven days), the decision to report must often be made right after the assault has occurred and they are feeling most vulnerable.  Fortunately, some states are adopting an approach similar to South Africa’s “just in case” exam, where a rape victim can have forensic evidence collected and preserved right after the assault. The victim then has a year to decide whether or not they want to file a complaint.

In Texas, for example, a sexual assault victim over 18 can go to a hospital and request a forensic exam without involving the police. This allows the victim to delay the decision about whether they want to file a legal complaint until they have had the chance to get emotional support and get farther along in the healing process. 

The Bottom Line

The decision to report a sexual assault to the police is a deeply personal one. Historically, victims were forced with an excruciating decision: endure the complaint process during the height of their trauma or run the risk of losing critical forensic evidence that might be the key to finding justice or preventing someone else from being assaulted.  Given recent research supporting the serial nature of many sexual assaults and the diverse offending behavior of many perpetrators, DNA is increasingly critical in solving serial crimes, whether involving sexual assault or serial murder.   

Every allegation of rape should be investigated as if it might have been committed by a repeat offender, not a ‘he said, she said’ situation where each assault is viewed separately.  We make those assumptions with other crimes like burglary so why not with sexual assault?  

Historically, investigators assumed that someone that assaults a stranger in a dark alley is nothing like the person that assaults their co-worker or girlfriend. In reality, the space between acquaintance rape and stranger rape is sometimes small. And, while no sexual assault victim should feel compelled to report sexual assault, preserving forensic evidence can sometimes be an empowering first step in regaining control over an event that was unfairly and viciously turned their life upside down. 


If you are interested in forensic psychology topics, please check out my forensic radio show, Thread of Evidence, and youtube true crime show, Unmasking a Murderer.