A youth was charged with robbery in company this week following an assault in Baulkham Hills on December 29.
Police said the boy and seven other youths allegedly approached three males in Gooden Reserve and started hitting them in an unprovoked attack.
A 17-year-old from Baulkham Hills suffered bruising to his face and had his iPhone, wallet and watch stolen.
He was taken to Westmead Hospital with minor injuries.
Police said the youth will likely be refused bail and he will face Parramatta Local Court on Friday.
Petrol bomb explodes
Police are appealing for information after a petrol bomb exploded under a bridge on Seven Hills Road, Baulkham Hills last week.
A resident heard a loud explosion at 7.35pm on December 30 and found a small device on fire.
With fire spreading the man kicked the metal device object into a nearby creek.
There were no witnesses.
Police search for intruder
Police are investigating an aggravated break and enter on December 30 in Baulkham Hills.
A 39-year-old woman was home at the time when she saw a man with a torch at the bottom of her stairs.
She woke up a family member and called police.
Police found a fly screen removed from a kitchen window and searched the area with a dog team but couldn’t find the intruder.
Four youths were fined for possessing fireworks in Bella Vista on December 30.
The men were sitting in a parked car on Charlemont Terrace when police stopped to talk to them at 11.50pm.
Police searched the vehicle and confiscated a basket of fireworks.