(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.

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 offenses including refusing to give detectives the passcode for his phone.