UPDATE 12.30PM: The NSW Police have identified the man killed in yesterday's shooting as Curtis Cheng, a 17-year veteran of the NSW Police finance department.
The shooter has also been identified as a 15-year-old boy of Iraqi-Kurdish descent who was born in Iran.
Police believe the shooting was politically motivated "and therefore related to terrorism".
The NSW Police have been in full consultation with Islamic communities and those communities have offered their full support and cooperation in the investigation.
Premier Mike Baird has called for NSW to 'stay together' as a community.
UPDATE: NSW Police Commissioner Andrew Scipione has spoken to the press about the fatal double shooting outside a police station in Parramatta.
A NSW Police Force employee was shot dead outside the Parramatta police headquarters today.
NSW Police Commissioner Andrew Scipione reportedly called the shooting "a brutal crime" and said it was part of a "deliberately, targeted attack".
Four five shots fired by man outside our office and in front of NSW police head quarters. Man shot down by guards and detectives ...Posted by Edwin Almeida on Thursday, 1 October 2015
The shooter, who reports say was of Middle Eastern appearance, was himself killed after an exchange of fire with NSW Special Constables.
A NSW Police spokesman said a critical incident investigation had been launched following the death of two people at Parramatta.
The incident occurred outside the NSW Police headquarters building on Charles St about 4.30pm after a number of shots were fired.
Commissioner Scipione said the death of the employee was a callous crime.
"We don't know the motive and we don't yet know who the gunman is but he has committed an appalling act of brutality," Commissioner Scipione said.
"Obviously this is a very distressing time for us all as we investigate all the circumstances.
"Currently we are attempting to identify a man who was seen to approach the victim and discharge a single shot.
"Subsequently, the assailant remained in the street here in Charles St before he then fired several further shots at our Special Constables as they emerged from Police Headquarters."
The Commissioner said in the exchange that followed the gunman was shot and killed.
"In viewing video footage, I have witnessed enormous bravery by those special constables who responded. They were brave and they were professional.
"Naturally we are supporting all our staff involved in this terrible episode."
The Commissioner urged the community not to jump to conclusions.
"We are keeping an open mind and I urge everyone else to do the same," he said.
A critical incident team from the State Crime Command's Homicide Squad will conduct an investigation over-sighted by the Coroner. This matter will be dealt with by way of a Coronial Inquest.
"My message to people across NSW is that there is nothing to fear. Go about your business including this weekend's major sporting events. We will do our job and get to the bottom of what has happened," Commissioner Scipione said.
Police employees across the state have been reminded of the safety provisions currently in place under the Alert 2015 provisions.
Anyone with any information is asked to call Crime Stoppers on 1800 333 000.
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