BOSTON -- A level 3 sex offender was arrested Saturday after he exposed his genitals on an MBTA train and followed a woman down the platform while committing a lewd act, according to transit police.

Jerome E. Reed, 49, of 8 Elene St., Mattapan, was charged with open and gross lewdness in a Dorchester court following the incident.

An MBTA inspector told police that Reed exited a train at Ashmont station with his genitals exposed at about 9:30 a.m. Reed then covered his genitals with his hands and began following a woman down the platform while committing a lewd act, said the inspector, who told police he was “absolutely disgusted” by Reed.

Two officers were sent to the station and Reed was arrested and transported to transit police headquarters.

"The female (Reed) was following, as well as a couple of other females, were ahead of him, so they had absolutely no idea this was going on," said Sgt. Preston Horton. "In my mind, he's a predator and he's not somebody I want on the MBTA."

Officials described Reed as a sex offender with a “violent and dangerous past,” including a prior conviction for open and gross lewdness. In 1993, he was also convicted of assault with intent to commit rape and indecent assault on a person under 14, according to the Mass. sex offender registry board.