A 22-year-old woman college student was allegedly harassed by an unidentified man near Mumbra railway station in the district, police said on Saturday.
While the incident took place on the evening of August 22, police are still trying to ascertain the culprit's identity, said an official.
The incident came amid widespread outrage over the sexual assault of two kindergarten girls at a school at Badlapur in the district.
The woman was walking home from college around 6.30 pm when a young man -- about 25 years old, thin with long hair -- stalked her, as per the complaint.
When the woman tried to call her brother for help, he gave her a shove. She raised alarm and some passersby chased the man but he succeeded in escaping, the police official said.
A First Information Report (FIR) was registered under Bharatiya Nyaya Sanhita (BNS) sections 74 (assault or use of criminal force to woman with intent to outrage her modesty), 78(1) (stalking) and 79 (word, gesture or act intended to insult modesty of a woman).
"We are taking this case very seriously and have launched thorough investigation," said an official of Mumbra police station.