Rape-kit testing shows that rapists also commit other serious, invasive crimes, according to new research

Larry McGowan is a sexual-assault offender, identified through the DNA testing of thousands of rape kits in Cleveland. He's been linked to raping six women—killing one of them—during a 15-year span and is serving a 25-years-to-life sentence.

Between rapes, McGowan was in and out of prison for stealing cars, felonious assault, arson, burglary, theft and robbery. He's also a suspect in another murder. But until thousands of previously untested rape kits in Cuyahoga County were tested, including those connected to McGowan, he had never been arrested or convicted of rape.

McGowan represents what researchers at Case Western Reserve University have concluded after analyzing the rape kits: that sexual offenders also tend toward committing other serious felonies—not just rape.

Most existing research about sexual offenders is limited because offenders must either be caught or self-disclose their crimes, said Rachel Lovell, research assistant professor at the university's Begun Center for Violence Prevention Research and Education at the Jack, Joseph and Morton Mandel School of Applied Social Sciences.

"New data on undetected sexual offenders—those who were never prosecuted for their crimes—connected to newly tested rape kits tells us that not only is repeated sexual offending more common than previously expected, but also about all the other crimes they commit," she said.

In other words, rapists don't exclusively commit rape; they're often the most aggressive types of criminals.

With access granted by the Cuyahoga County Prosecutor's Office, the researchers have studied data from Northeast Ohio's nearly 7,000 untested rape kits, an effort that has resulted in hundreds of convictions.

The research findings, published in the journal Criminal Justice and Behavior, show that sexual offenders have very high "serial criminality rates." Criminality is measured by offenders who have multiple arrests for serious crimes.

In addition:

• 7% have at least one arrest for murder;
• While one in five are rapists who primarily commit rape ("specialists"), 40% are committing lots of varying crimes ("generalists");
• Only a third had a rape arrest in their history. "Like McGowan, just because he didn't have a rape arrest, didn't mean that there weren't previous rapes," said Lovell.