An Edmonton police officer was acting in self defence when he shot a 17-year-old armed with an aluminum bat and a knife last February, said investigators Monday.

Cyrus Green was shot Feb. 4th after police responded to several complaints of violent robberies near the Coliseum transit station just after midnight.

Two officers at a road block told Green to drop his weapons, but instead he raised them to shoulder height and continued to walk towards police, said Clifton Purvis, with the Alberta Serious Incident Response Team.

"He said words to the effect, 'You are going to have to shoot me,'" said Purvis.

When Green still advancing on the officers at about three metres away, an officer fired three times, hitting Green in the chest, said Purvis. 

The officer had been with the force for five years.

Green had a long criminal record filled with robbery and assault convictions and had spent much time in jail at the Edmonton Young Offender Centre, said Wallis Kendal, who works with troubled youth in Edmonton.

"He ended up in EYOC on a number of occasions due to the fact of drinking and having things go wrong when he was drinking," said Kendal.

Green was legally impaired by alcohol at the time of the shooting with trace amounts of marijuana in his blood, said Purvis.

Purvis spoke to Green's mother and sister Monday about the conclusion of the investigation.

"This is a huge tragedy for their family and they're overwrought with grief," he said.

"I don't think frankly anything that the investigation would have uncovered would diminsh that grief."

A friend of Green's later pleaded guilty to the string of violent robberies at the Coliseum LRT station that led to the police shooting.