Ontario's Special Investigations Unit (SIU) has cleared Ottawa police of any wrongdoing in the shooting death of a suspected bank robber who was carrying a fake pistol.

The shooting occurred on March 6 when police were called to investigate a robbery at a TD Bank on Montreal Road in the city's east end.

According to the SIU, police saw the suspect, 27-year-old Paul Jeffrey, fleeing the area with what they thought was a real pistol. The SIU said police chased Jeffrey on foot, and he turned to one of the officers and said he would shoot.

As the chase continued, he pointed his gun at the officers.

"This prompted several officers to shoot at Mr. Jeffrey," the SIU said Friday in a news release.

Jeffrey died from gunshot wounds, although the SIU was not able to determine which of the four officers who shot at Jeffrey killed him.

The SIU said that according to the Criminal Code, police officers have the authority to use lethal force against a fleeing felon if they believe on reasonable grounds that the force is necessary to protect themselves or others from death or serious injury. The officers must also believe that there was no other way to stop the fleeing felon.

"Here, the subject officers were attempting to apprehend was a man who had just robbed a bank and had a replica handgun in his possession," SIU director Ian Scott said in the news release.

"Even though the pistol was not real, Mr. Jeffrey behaved in a manner that would cause a reasonable person to conclude that it was real."

Scott said what matters, legally, isn't whether the threat was real but whether the officers believed it was real.

"The law is clear that a police officer may rely upon an honest and reasonable, but mistaken, belief in apprehending death or serious bodily harm before responding with lethal force," he said.

"Here, I am of the view that the subject officers had an honest and reasonable belief that the Mr. Jeffery was an armed fleeing felon who was prepared to use imminent lethal force against one or more of them."

The SIU is a civilian agency that investigates cases of serious injury, including allegations of sexual assault, and death involving the police in Ontario.