Two male teenagers were robbed as they walked home from Crestwood High School on March 10.
The youths, both 15, told police they were walking through Crestwood Reserve at 3.10pm when two men assaulted them and took a mobile phone.
Police would like to speak to a woman of Asian appearance who helped one of the the youths after the incident.
Police would also like to speak to two men who may be able to assist with investigations.
One was described as being 18 years old, of Middle Eastern appearance with chubby build and black hair, wearing a white/grey t-shirt. He had a plaster cast over his right wrist and hand and a black tattoo on the inside of one forearm.
The second male is thought to be 18 years old, Caucasian, skinny build with facial hair and wearing a black T-shirt and blue jeans.
Anyone with information can call Castle Hill detectives on 9680 5342 or Crime Stoppers on 1800 333 000.
In other police news:
Grocery theft alleged
A Castle Hill woman, 30, received a criminal infringement notice for allegedly attempting to steal $128 worth of groceries from a supermarket in Castle Towers on March 12.
A loss prevention officer told police he allegedly saw the woman leave the store with a trolley full of items at about 4.53pm.
Driver caught doing 65km/h over speed limit
A Castle Hill woman, 45, was caught driving at a speed of 115km/h in a 50km/h zone in Castle Hill on March 7.
Highway Patrol officers were doing speed enforcement at Old Castle Hill Road when they spotted the woman’s black Toyota Corolla speed past at 11.50am.
The woman reportedly told police she was speeding because she ‘‘was having a good day’’.
She was given a traffic infringement notice, her licence was suspended for six months and she was fined $2197.