Australian police have raided a mosque a 15-year-old attended before he shot dead a police employee in an apparent terrorist attack, as the authorities pledged to work with Muslim leaders to combat "preachers of hate".
As investigations continued into Iranian-born Farhad Jabar Khali Mohammad's motivations, it emerged that his sister Shadi had left the country on Thursday on a flight to Istanbul. It is believed she may have been attempting to travel to Iraq or Syria, where Islamic State in Iraq and Syria (ISIS) militants hold vast swathes of territory.
Farhad's older brother apparently tipped off police that the 15- year-old had conducted the attack.
More details have emerged about Friday's shooting, which occurred outside a police headquarters in Parramatta, a commercial hub west of Sydney's central business district.
RECENT EVENTS LINKED TO EXTREMISM
The Australian authorities are grappling with a rise in violence perpetrated by teenagers at home as well as working to halt the flow of those attempting to travel to Syria to fight with Islamic extremists. Below is a timeline of recent events in Australia linked to militant extremism.
Farhad Khalil Mohammad Jabar, 15, shoots dead a civilian employee outside a police station in Sydney and is killed by officers at the scene.
Police raid a Melbourne home following a tip-off and arrest a 17-year-old boy after finding three improvised explosive devices.
Five teenagers are arrested in Melbourne in connection with an alleged plot to carry out a terror attack at an Anzac Day memorial event. A 14-year-old boy in northern England is later convicted of inciting the attack.
Police arrest and charge Omar Al-Kutobi and Mohammad Kiad with planning to carry out an imminent terrorist attack. Prime Minister Tony Abbott announces plans to toughen citizenship laws and clamp down on citizens inciting hatred.
The national terror threat for all police is raised from medium to high.
Self-styled Muslim cleric Man Haron Monis takes 18 people hostage in a Sydney cafe. Two hostages are killed, and he is shot by police after a 16-hour stand-off.
Farhad apparently paced around and caused some commotion outside the police building before killing Mr Curtis Cheng, 58, a civilian police employee believed to be from Hong Kong. Farhad then shot at police and was killed.
It is believed Mr Cheng, an accountant and a father of two, may not have been specifically targeted and might have been killed because he was the first person Farhad saw.
Mr Cheng's family said in a statement: "He was humorous, generous of heart, and always put the family first. He has set a tremendous example for us as a family."
Police said in a statement yesterday they had searched the Parramatta mosque, which is only a short distance from where the attack occurred. The warrant was undertaken with the full cooperation of the mosque's leaders, police said.
Police were reportedly searching for a black backpack in which Farhad apparently carried the gun. He is believed to have acted alone and had changed into a black robe before carrying out the attack.
"The boy, he did it alone. He died, and his motive died with him," Mr Neil El-Kadomi, the mosque's chairman, told ABC News.
"He is not known in the mosque. Because he was very quiet, nobody noticed him. He came to the mosque to heal himself before he did the crime, which is wrong."
Mr El-Kadomi joined other Islamic leaders in Australia in condemning the crime.
"We don't agree with what happened in Parramatta," he said.
"We have got nothing to do with it, and I hate the linking of the mosque with the crime."
Police also searched Farhad's family home in North Parramatta and seized computer equipment. The teenager had no criminal record and was not known to police, who are trying to understand how he was able to obtain a gun.
The shooting follows a series of attacks and foiled plots by Islamic extremists in Australia.
Prime Minister Malcolm Turnbull and New South Wales state Premier Mike Baird held a phone conference with Muslim community leaders after the shooting to discuss efforts to combat radicalisation.
Foreign Minister Julie Bishop said Mr Turnbull sought to convey the message that "we have a remarkably cohesive society, respect is key to that and everyone (should) work together to expose preachers of hate".
"So, we are certainly reaching out to the leaders of the Muslim community," she told ABC Television.
"It is the families that will be a frontline of defence against radicalised young people... so, we will be working very closely with them."