A man, who allegedly performed an indecent act in front of a woman on the Illawarra line, may have thought he had got away with it.
If so, he was mistaken because police swooped six days later.
A Carlton man, 28, was arrested and charged yesterday (Thursday) over the incident, which occurred last Friday (October 9).
A police statement said, about 2pm, a woman, 23, was travelling on a southbound train from Town Hall, when an unknown man attracted her attention and allegedly committed a sexual act.
After leaving the train, the woman notified police, and officers from the Police Transport Command began an investigation.
"Following inquiries, a 28-year-old man was arrested at Hurstville Railway Station just after 2pm today (Thursday)," a police statement said.
"During a search of the man's backpack, police sezied a knife and knuckle dusters.
"He was taken to Kogarah Police Station and charged with carry out sexual act with another without consent, possess or use a prohibited weapon without permission and custody of knife in a public place.
"The Carlton man was granted conditional bail to appear before Sutherland Local Court on Tuesday November 3."