BRISBANE, Australia (AP) — Australian detectives suspect the deaths of an elderly couple in their Brisbane home is a “terrorism incident” perpetrated by a knife-wielding man who was shot dead by police, officials said on Friday.

Raghe Abdi, 22, threatened police with a knife before he was shot dead on a highway on the outskirts of Brisbane on Thursday morning, officers said.

The bodies of an 87-year-old man and an 86-year-old woman were found in their home later Thursday near where Abdi died, Queensland state Police Deputy Commissioner Tracy Linford said.

Linfold declined to detail how they had died but homicide detectives had found evidence that Abdi had been in the house, she said.

Police Commissioner Katarina Carroll said the known extremist had been acting alone.

“We had no choice but to declare this as a terrorism incident,” Carroll told reporters.

Australia Federal Police suspect Abdi had been influenced by the Islamic State group. He was arrested on suspicion that he was trying to join extremists when he attempted to depart Brisbane Airport for Somalia in May 2019. He was released without charge due to insufficient evidence, but his passport was canceled.

In June 2019, he was charged with further offences including refusing to give detectives the pass code for his phone.

He was free on bail and had been forced to wear a GPS tracking device, which he had cut off before he was shot.