The fatal shooting of a civilian member of Sydney police by an Iranian teenager Friday is believed to be “linked to terrorism,” Australian police said Saturday. The victim has been reportedly identified as Curtis Cheng, a finance worker who had worked for the New South Wales (NSW) police force for 17 years.

The shooter, a 15-year-old boy of Iraqi-Kurdish background, opened fire outside the NSW state police headquarters on Charles Street in the business district of Parramatta. Cheng was shot with a handgun at close range as he left work, authorities reportedly said. The Iran-born teen was shot and killed by responding officers.

“We are a long way from establishing a full picture of this man. His exact motivation still remains a mystery to us," Police Commissioner Andrew Scipione said, according to the Associated Press. "We believe that based on the information that we have that this was politically motivated. If it's politically motivated violence, then under our definition, it is deemed necessarily an act of terrorism."

Scipione did not reveal details that led to the conclusion that it was a terror incident, but said the gunman, who lived in the Parramatta area, acted alone. He added that it was unclear if the teenager was radicalized by someone.

"We are not sure whether he was targeted because he came from a police facility," Scipione reportedly said. "But he was certainly targeted in terms of the shooting. It was a direct shooting. Certainly wasn't a ricochet. It was a targeted shot that took his life."

Police also said that the teenager was unknown to police or counterterrorism officials and that authorities had received no warning that a shooting was imminent.

Earlier, the Daily Telegraph reported that police had received a warning of the attack through intelligence sources.

"There's no doubt that this tragedy will echo around the world, as people try and understand how someone so young could admit such a hideous crime," NSW Premier Mike Baird said, according to Reuters.

Australia has been on heightened alert after last year’s attack in Sydney. The country also stepped up counterterrorism efforts in recent months over a string of homegrown terrorism crimes involving teenagers.

In September 2014, police shot dead a Melbourne teenager after he stabbed two counterterrorism officers, while in December, two people were killed after a lone gunman, Man Haron Monis, held 18 people hostage at a central Sydney cafe.

"It is a shocking crime. It was a cold-blooded murder," Prime Minister Malcolm Turnbull reportedly said Saturday in Melbourne. "It was doubly shocking because it was perpetrated by a 15-year-old boy. And it underlines the importance of families, communities, leaders being very aware of whether young people are becoming radicalized."