Police are investigating a robbery which occurred in Dandenong last month, Victoria Police say.
Investigators have been told a 20-year-old woman was at a library at the corner of Thomas Street and Walker Street about 9.20pm on Wednesday 14 June.
She was approached by a group of five females.
One of the group punched her to the face, dragged her to the ground and sat on her while another of the group stole her phone.
The group left and were last seen heading along Thomas Street.
Investigators have Identified four teenage girls in relation to the matter.
A 13-year-old girl from Carrum Downs has been charged with affray, robbery and theft.
A 15-year-old girl from Carrum Downs has been interviewed and released pending summons.
Two other girls are yet to be interviewed and police are still attempting to identify a fifth.
Investigators have released an image of a woman that they believe may be able to assist with their enquiries.
Anyone with any information is urged to contact Crime Stoppers.