A MAN was arrested in Sydney today after a second stabbing took place in the Australian capital.

A bishop and three churchgoers were injured in the attack which took place during a televised service this evening, police said.

A video on social media shows a man dressed in black approaching a cleric at the altar of Christ the Good Shepherd in suburban Wakely and appearing to stab him repeatedly in the head and upper body.

It came two days after a lone assailant stabbed six people to death in a busy Sydney shopping centre on Saturday and injured more than a dozen others.

Police shot and killed the homeless assailant Joel Cauchi during his attack in the Westfield Bondi Junction mall near Bondi Beach.

The force is examining why Mr Cauchi targeted women while avoiding men, New South Wales Police commissioner Karen Webb said.

Ms Webb said that detectives would question his family in a bid to determine his motive.

Andrew Cauchi said his son, who suffered from schizophrenia, had targeted women “because he wanted a girlfriend and he’s got no social skills and he was frustrated out of his brain.”

The 76-year-old told reporters outside his home in Toowoomba in Queensland state: “To you, he’s a monster. To me, he was a very sick boy. Believe me, he was a very sick boy.”

The only man killed was Faraz Tahir, a Pakistani refugee who worked at the mall as a security guard.

Mr Tahir had not been armed.

Ms Webb said most of the 12 victims who survived their wounds were also women.

There was no immediate indication the two stabbings were connected.