A coroner's inquest began Monday into the November 2007 death of Robert Knipstrom, who was Tasered during a struggle with a rookie RCMP officer.

Knipstrom, a 36-year-old arbourist, was taken to hospital but died four days later.

Knipstrom had gone to EZ Rental in Chilliwack to return a wood chipper. The store's owner, Russ Walsh, told the inquest that Knipstrom was twitchy and erratic.

When Knipstrom refused to leave the store, police were called.

The officer who tried to arrest Knipstrom testified that Knipstrom lunged at him.

He said that he used his pepper spray, his baton and his Taser to get him under control.

"I was trying to get away from him ... he was chasing me around the store ... I was getting tired," the officer testified.

"This guy seemed bound and determined to hurt me ...I was running out of options."

The officer cannot be identified because he now works undercover.

Mike Berube, a former worker at the store, said Knipstrom did not appear aggressive to him.

"From what I saw he just wanted to get away. And the two officers just wanted to hold him down," Berube told reporters outside the hearing. "It didn't look like they were rushing him. It didn't look like he was rushing them. They were just trying to corral him."

Knipstrom was Tasered twice. Police pulled the Taser probes from his back after taking him down.

Knipstrom's father later arrived to calm his son down.

An autopsy showed the cause of death to be lack of oxygen and the drug Ecstasy.

The role the Taser played will be examined later in the inquest.

With a report from CTV British Columbia's Lisa Rossington