Winnipeg police officers had to Taser an armed-robbery suspect two times during a chase Wednesday before they managed to make an arrest.

Police were called on Wednesday at 1:30 p.m. after reports of an armed robbery at a clothing store on St. James Street near Portage Avenue.

The suspect peddled off on a bike and officers found him near the corner of Empress Street and Wellington Avenue. He then confronted police with a knife and officers fired their Tasers at him in response, Const. Tammy Skrabek said.

The Tasers didn't work and the man took off running with police in pursuit, dropping his backpack in the process. A search of the bag uncovered a .22-calibre rifle inside, Skrabek said.

The man then unsuccessfully tried to steal a locked car with the driver still inside before police stopped him again on Empress.

The man still had a knife on him and resisted arrest, Skrabek says, so police fired their Tasers again and took him down.

"For a variety of reasons, the Taser can be ineffective," Skrabek said.

The 28-year-old man was charged with two counts of robbery, five counts of assaulting a peace officer and numerous counts of possessing and concealing a restricted firearm, among other offences.

Taser not always foolproof

Const. Colin Anderson, an instructor on Taser use with the Winnipeg Police Service, said several unanticipated factors can make a Taser less effective.

Winnipeg police Const. Colin Anderson

Const. Colin Anderson is an instructor on Taser with the Winnipeg Police Service. (Jaison Empson/CBC)

The probes that are ejected from the device conduct an electrical charge, but they don't always hit the target. Loose or baggy clothing can also get in the way, he added.

Skrabek said the person who narrowly avoided being carjacked at knifepoint serves as an important reminder to Winnipeg drivers to keep their vehicles locked.

"As weather is getting warmer, we tend to have our windows open, we drive with things in the car seat. This happened at 1:30 in the afternoon," Skrabek said.

"It's a time when we're generally rushing around, we're going to meetings, we're picking up kids, we're doing shopping, we're in and out of vehicles and we forget to lock our doors, we forget to roll up our windows and we're not anticipating that an incident as serious as this is going to happen in such a public area."

Justified in shooting suspect

Winnipeg police constable Tammy Skrabek

Winnipeg police Const. Tammy Skrabek said officers fired Tasers at a robbery suspect on two occasions Thursday before they managed to take him down. (Jaison Empson/CBC)

Officers also had no idea the suspect had a concealed gun on him before the chase began, Skrabek said.

"This could have been a potentially deadly encounter for our officers,"  Skrabek said. "Our members were warranted in this case to use deadly, to use a firearm ... because of the fact that he was armed with a knife."

"Officers did a really good job of controlling the situation: they managed not to resort to deadly force, to take the suspect into custody, thereby preserving his life in the process."