The Vancouver police officer who shot and killed Paul Boyd three years ago said Wednesday that he thought he had run out of options for dealing with the bipolar man.

Boyd, 39, was killed in August 2007 after police responded to a report of a bus stop assault on Granville Street. When officers arrived, Boyd started fighting with them and swinging a bicycle chain.

Const. Lee Chipperfield shot him eight times.

"I didn't want to shoot Mr. Boyd. That's the last thing I wanted to do," Chipperfield said at a coroner's inquest into the death.

He said that when he first arrived on the scene, he thought he would be dealing with an assault. Someone had called 911, thinking that Boyd had pinned a man to the ground, but another witness testified that Boyd was kneeling by himself and shouting.

"This was a situation that [Chipperfield] did not expect. He was confronted with something completely different than what he was dispatched to, and that obviously resulted in this escalation that got us to this tragic outcome," Tom Stamatakis of the Vancouver Police Union told CTV News.

Chipperfield said he arrived on Granville Street near 16th Avenue to see Boyd with two officers. One officer fell to the ground and the other was trying to use a baton against Boyd, who was swinging the chain.

Chipperfield said he drew his gun alongside other officers and shouted commands, but Boyd didn't comply and continued approaching with the chain, making grunting and snarling noises.

The officer testified that he was worried Boyd was going to attack him or someone else, and that police had run out of options.

"I think there needs to be more attention paid to where everything broke down before we ended up having this interaction with Mr. Boyd that resulted in this tragic outcome," Stamatakis said.

Chipperfield said he thought Boyd might have been wearing body armour because he kept advancing after each shot. He fired until Boyd stopped getting up -- including one shot to the head.

Chipperfield was also asked about testimony given by another officer, who told the inquest he ran in and took the bike chain away from Boyd in between shots. Chipperfield testified that he didn't see that, and if he'd known Boyd had been disarmed he would have stopped shooting.

He ended his testimony by apologizing to Boyd's family for the grief he'd brought them.

Boyd's father David told reporters outside the inquest that he still had questions about the shooting.

"It wasn't clear whether [Chipperfield] honestly felt under threat or whether this was what he used afterwards to justify his actions," David Boyd said.

He added that he was surprised to hear that Chipperfield didn't realize Boyd had been disarmed.

"That's shocking to me that a police officer who is out on the street is so unaware of what is happening around him."

With a report from CTV British Columbia's Maria Weisgarber