Officers from Transit Divisional Response Unit are appealing for public assistance following a number of tagging incidents last month.
Investigators believe a man attended North Melbourne Railway Station about 5.35pm on Wednesday 27 November.
He attended the area near the lift on platform 4 and proceeded to tag the wall before boarding a train.
The man got off the train at Keilor Plains Railway Station and tagged the outside of the carriage.
He then climbed onto the tracks and tagged a bus stop sign as he left the station.
Investigators have released CCTV and images of a man that they believe may be able to assist with their enquires.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au
