Nova Scotia's Serious Incident Response Team has cleared a police officer of any criminal wrongdoing in the death of a man in the Halifax Regional Police lock-up more than two years ago.

The police watchdog, however, says the officer's conduct may have breached policy and has referred the case back to police for possible discipline.

SIRT was called in to investigate after a 52-year-old man who was locked up for public intoxication died of a brain injury. 

The man, who is identified in SIRT's report by the initials AP, was taken into custody on Sept. 5, 2013. He had apparently fallen down on a dirt path near Sylvia Avenue in the Spryfield area.

AP was well-known to police as a chronic alcoholic who had been picked up in the past for public intoxication.

The man was put in cells at the police station on Gottingen Street and left to sleep it off.

The man was checked by an officer every 15 minutes. However, the officer did not try to rouse the man, as required by policy. SIRT noted the policy isn't always followed if the inmate simply appears to be sleeping.

Untreatable brain injury

It wasn't until a second officer checked the cells about six hours after AP's arrest that he was found unresponsive. He was rushed to hospital where doctors found bleeding on the brain and a serious, untreatable brain injury. He died three days later.

On Wednesday, a spokeswoman with Halifax Regional Police said the force did an audit on the way it cares for people in custody and changed its policy.

"It has also resulted in an enhanced model of care for prisoners, particularly those who are identified as being at-risk," Const. Dianne Woodworth said in an email.

She said police reviewed the matter when AP died, but determined is was a policy issue rather than a disciplinary matter.

SIRT said in its report there is no evidence police knew AP had struck his head prior to his arrest.

The team sought medical opinions from three experts. Those experts said while it would have been preferable to intervene earlier and seek medical help, it's not clear this would have prevented AP's death.

But the fact the officer failed to properly check AP is "certainly of significant concern," SIRT director Ron MacDonald wrote in his report, released Wednesday.

"His actions may well constitute a form of civil negligence and a breach of policy."

The agency has referred the matter back to police for possible disciplinary action.