Matthew Johnson, 31, of Allston was arrested Tuesday afternoon after he allegedly trespassed along MBTA train tracks in Jamaica Plain.
Transit Police said the witnessed Johnson climb onto the commuter rail platform from the track at Forest Hills Commuter Rail station after receiving calls about the alleged trespassing.
Upon their investigation, Transit Police said they found that Johnson had an outstanding warrant in existence for his arrest out of Dorchester District Court for Failure to Register as a Sex Offender.
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