When the Louisiana parole board met in October to discuss the potential release of a convicted murderer, it called on a doctor with years of experience in mental health to talk about the inmate.

The parole board was not the only group paying attention.

A collection of online trolls took screenshots of the doctor from an online feed of her testimony and edited the images with A.I. tools to make her appear naked. They then shared the manipulated files on 4chan, an anonymous message board known for fostering harassment, and spreading hateful content and conspiracy theories.

It was one of numerous times that people on 4chan had used new A.I.-powered tools like audio editors and image generators to spread racist and offensive content about people who had appeared before the parole board, according to Daniel Siegel, a graduate student at Columbia University who researches how A.I. is being exploited for malicious purposes. Mr. Siegel chronicled the activity on the site for several months.

The manipulated images and audio have not spread far beyond the confines of 4chan, Mr. Siegel said. But experts who monitor fringe message boards said the efforts offered a glimpse at how nefarious internet users could employ sophisticated artificial intelligence tools to supercharge online harassment and hate campaigns in the months and years ahead.