A man “with a deep voice” grabbed a teenage girl by the hair and made lewd comments to her while she was walking past a car park in Towcester.
The incident happened between 12.30am and 1am on Saturday.
The 16-year-old girl was walking past a car in the car park at the junction of Vernon Road and Watling Street when the passenger in the car reached out, grabbed her hair and made “a suggestive comment”.
As she ran away past the bus stop next to the car park she was also grabbed by the waist by another unknown person.
The man in the car is described as a man with a deep voice.
Witnesses to this incident, or anyone with information, can call Northamptonshire Police on 101. Alternatively, information can be given anonymously to Crimestoppers on 0800 555 111.