A Winnipeg police officer who was at a 2008 confrontation that led to Michael Langan being shocked by a Taser told an inquest into the teen's death that he ordered his partner to deploy the stun gun over concerns about his partner's safety.

Langan, 17, was subdued by a police Taser during a confrontation with officers in the city core on July 22, 2008. He died in hospital a short time later.

Michael Langan

Michael Langan, 17, died after being shocked by a Winnipeg police Taser stun gun in 2008. (Manitoba Metis Federation)

The inquest, which began Monday, has heard that police were searching for a robbery suspect when they found Langan in a back lane, holding a knife and refusing to put it down.

One of the police officers who was there, Michael Temple, testified on Tuesday that he yelled at his partner to deploy the Taser after Langan was ordered at least twice to drop the knife.

The use of the electric stun gun was appropriate in this case, Temple said, citing concerns over his partner's safety.

Temple said the officers had approached Langan in a police cruiser, thinking they were going to chase him on foot. But they didn't see the knife right away and by then he was about a metre away from the vehicle, he said.

"Three to four feet is very close proximity for a knife assault," Temple told the inquest, adding that Langan threw his jacket onto the ground and was acting aggressively before he was subdued by the Taser.

"When he threw the jacket on the ground, he had an angry, crazy look in his eye," he said.

Witness heard yelling after Taser used

The officer's testimony differs from that of Jordan Wolfman, who said he heard officers yelling at Langan after the Taser was deployed.

Earlier on Tuesday, Wolfman said he was doing maintenance work on the grounds of the national virology lab on Arlington Street when he heard a police car speeding down the street, then saw two officers getting out of the vehicle and walking toward the suspect.

Wolfman testified that he didn't hear Langan say anything, nor did he see him do anything, but he heard the officers yell, "Drop the knife!" after Langan was shocked by the Taser.

During cross-examination, a lawyer for the Winnipeg Police Service asked Wolfman if it was possible the incident happened too quickly for him to remember the exact sequence of events.

Wolfman said it's possible, but he stood by his version of events.

Temple testified that Langan still had the knife in his hand after he fell to the ground, which would explain why officers were seen yelling at the teen after he was shocked with the Taser.

The officer, who is also a Taser instructor, told the inquest that pepper spray wasn't used in Langan's case because it's not as effective when a suspect is too close to officers and poses a threat.

Had the officers known from the start that Langan was carrying a knife, they would have tried to contain the suspect from a distance and called for backup, Temple told the inquest.

A paramedic is also expected to testify at the inquest. The first phase is expected to last several weeks.

Inquest counsel are questioning witnesses, as well as lawyers representing Taser International, the company that manufactures the stun guns, and the Winnipeg Police Service.