A 76-year-old man was shot and killed in a southeast garage by a police officer on Tuesday and investigators say the man was holding a large, butcher knife when he approached officers.

Police responded to a 911 call from a home in the 0-100 block of Sunmount Crescent at about 11:00 a.m. and say someone screamed for help and then hung up the phone.

When officers arrived at the scene they were approached by a 21-year-old man who was covered in blood and was carrying a cell phone and a knife.

Officers directed the man to drop the knife and he complied and said he was attacked inside the home by a family member.

A loud noise was heard coming from the detached garage and police approached and forced open the door.

A vehicle was found idling inside and had a hose running from the exhaust to the back passenger window.

Police say there was no one inside the vehicle and that a table saw had been turned on, which turned out to be the noise they heard.

A bloodied man with a wound on the side of his neck came out of a corner holding a large, butcher knife and confronted officers.

One of the officers fired his weapon and the man collapsed on the floor.

Officers attempted to provide medical assistance but the man died at the scene.

The man was found to have also suffered from a number of stab wounds in addition to the cut on his neck.

He has been identified by neighbours as Robert Crowle and the other man is believed to be his grandson.

ASIRT is investigating and will concentrate on the circumstances that led up to the confrontation between police and Crowle.

Calgary police are also investigating and will be looking at the events that happened between the two men before they arrived on scene.