The numbers are going down, but the problem is still very real: online sex predators. The FBI estimates that a staggering 250,000 adults seek sex with youths on a daily basis.
But a new digital forensic tool developed by Purdue Polytechnic Institute faculty could be used to help law enforcement identify sex offenders most likely to attempt in-person meetings with child victims. The Chat Analysis Triage Tool (CATT) employs an algorithm to automatically analyze chats between minors and offenders. By examining a suspect’s word usage and conversation patterns, it can determine whether that suspect is “fantasy-driven” or “contact-driven.”
The latter is the main focus: Contact-driven predators want to meet the minor for sex in the physical world. Fantasy-driven predators, by contrast, are more interested in “cybersex.”
"If we can identify language differences, then the tool can identify these differences in the chats in order to give a risk assessment and a probability that this person is going to attempt face-to-face contact with the victim," said Kathryn Seigfried-Spellar, an assistant professor of computer and information technology.
While fantasy-driven predators tend to move on quickly from one youth to another, contact-based individuals often carry on chats for weeks or months to groom their victims before setting up a face-to-face meeting.
"Meaning that we could potentially stop a sex offense from occurring because if law enforcement is notified of a suspicious chat quickly enough, CATT can analyze and offer the probability of a face-to-face," Seigfried-Spellar added. "We could potentially prevent a child from being sexually assaulted."
Research on the project was done using data taken from online conversations provided voluntarily by law enforcement around the country, and included an examination of more than 4,300 messages from 107 online chat sessions involving sexual offenders. CATT was developed by three co-principal investigators — Seigfried-Spellar; Taylor Rayz, an associate professor and ML/NLP specialist; and Marcus Rogers, who has an extensive background in digital forensics tool development and also serves as department head for computer and information technology.
The team plans to turn the tool over to several law enforcement departments for a trial run. CATT could be handling real-world cases perhaps as early as the end of this year.