A teenager accused of fatally stabbing a Scientologist at the church's Sydney headquarters was trying to visit his mother who was undergoing a so-called purification ceremony, it's been revealed.
The 16-year-old is undergoing a mental health assessment after allegedly attacking a 24-year-old Church of Scientology member on Thursday at the organisation's Australasian headquarters in Chatswood.
It's expected the teenager, who police say also stabbed another man aged 30, will be charged over the incident.
AAP has been told the accused was visiting the centre where his mother was to undergo a "purification ceremony".
The deceased, a Taiwanese national, was stabbed in the neck while escorting the 16-year-old off the church grounds.
It's understood the victim was a parishioner studying at the sprawling bush centre.
Detectives say the teenager was asked to leave due to a "domestic incident" on Wednesday and that he produced a sharp 25-centimetre long kitchen knife while on the driveway.
Police officers arrested the boy after drawing their stun guns as ambulance and fire crew arrived on the scene.
The teenager underwent a mental health assessment at Royal North Shore Hospital on Friday.
Detective Chief Inspector Simon Jones on Thursday said the assailant was of "Asian descent". News footage showed him being led away by police with his cuffed hands inside evidence bags.
A Scientology spokeswoman described the 24-year-old victim as a "beloved" member of the church.
The massive 13,500 square metre building at Chatswood - which was opened in September 2016 - is the largest Scientology centre outside the United States.
The site formerly housed the National Acoustic Laboratory and was purchased by the church for a reported $37 million in 2014.
