According to the police report, a 21-year-old Madison man told police had a casual conversation with the suspect before both entered the restroom at the East Towne Mall about 12:30 p.m. Saturday.
Once they were inside, reports say the suspect inappropriately grabbed the 21-year-old, telling him that he had just gotten "out of the pen." The victim broke free and called police.
The Milwaukee Journal Sentinel reports officers found the man, who told police he had been staying at homeless shelters since his release from prison.
Police say the man faces a tentative charge of second-degree sexual assault.