FALL RIVER — A 45-year-old Attleboro man who sexually assaulted an intellectually disabled man was convicted in Fall River Superior Court and sentenced to serve five years in state prison, Bristol County District Attorney Thomas M. Quinn III announced.

Steven Thibeault pleaded guilty to a multi-count indictment charging him with rape, indecent assault and battery on an intellectually disabled person, assault and battery on an intellectually disabled person and possession of child pornography.

The defendant, while living with the intellectually disabled man in 2012 and 2013, forcibly performed oral sex on the victim. The victim eventually reported the sexual assault to a case worker with the Massachusetts Department of Mental Health, sparking the investigation and eventual arrest of the defendant.

While out on bail, Massachusetts State Police were informed that the defendant was sending pornographic images of young boys to other unverified Twitter users. The defendant was also found to be in possession of more than 2,000 images of young boys in various states of undress on his computer.

Judge Thomas McGuire sentenced the defendant to serve five years, to five years and a day, in state prison, to be followed by five years of supervised probation. The conditions of probation include GPS monitoring, no contact with children under 16, no contact with the victim, complete mental health counseling and register as a sex offender.

The case was prosecuted by Assistant District Attorney Melissa Hendrie.

“The defendant’s conduct is extremely disturbing. He took advantage of a vulnerable victim,” District Attorney Quinn said. “The sentence imposed by the court holds the defendant accountable for his offensive conduct without the victim having to testify in court.”

--Bristol County District Attorney's Office