EDMONTON -- Alberta's police watchdog says officers will not face any charges for fatally shooting a 30-year-old armed man in a mall parking lot in 2017.

On Monday, the Alberta Serious Incident Response Team released its findings into the Sept. 9, 2017, shooting, detailing the events that led up to the unidentified man's death.

A day earlier, police executed a search warrant at a home linked to the man, who was the subject of a meth-trafficking investigation.

Officers also received a tip that the man possessed firearms. They deemed the warrant a "high-risk situation" and decided to try to arrest him while he was on foot or in his vehicle.

They located him the following day at around 8 p.m. as he drove a white Mercedes-Benz sedan with two woman as passengers, according to ASIRT.

Unmarked police vehicles followed him to the Westmount Mall parking lot, where they boxed in his vehicle and activated their emergency lights.

Officers identified themselves and ordered everyone in the car to get out with their hands up, and while the occupants initially showed their hands, none of them tried to exit the vehicle slowly as requested.

"This led to a brief standoff, estimated as lasting for approximately 20 seconds," ASIRT said.

The man eventually dropped his hands, reversed the vehicle and rammed into a police truck behind him.

He then plowed forward, ramming the police car in front so hard its driver's side airbag deployed.

Officers then fired two canisters of tear gas into the car through an open window, and while the occupants were distracted police boxed in the vehicle once again.

As police shouted at the two women to get out of the car and one officer tried to grab one of the passengers, the man reached for a handgun in a black satchel-style bag around his neck.

That prompted police to fire a non-lethal ARWEN baton round that struck the man but didn't cause him to drop the gun.

"The man pulled and pointed a loaded gun at police. Indeed, he went further and actually fired at police," said ASIRT Executive Director Susan Hughson.

The man's shots went through the dash of the car. As he pointed his gun again at an officer, police fired the lethal shot, leaving the man slumped over in his car.

The women and police officers weren't injured and police recovered the man's gun, a black nine-millimetre, from the car floor.

A toxicology exam later found that the man had methamphetamine in his system at his time of death, and more meth was found in his satchel bag.

After a more than two-year investigation, ASIRT determined police had no choice but to take lethal action.

"Officers used many techniques and tools to attempt to apprehend the man without lethal force, including the flash-bangs, CS gas and the ARWEN launcher," said Hughson. "The man's conduct clearly presented a risk of grievous bodily harm or death to the officers."

Hughson concluded evidence would not support reasonable grounds to believe the officers committed a crime.

ASIRT investigates all cases involving Alberta police that result in serious injury or death to a person.