HALIFAX -- Nova Scotia's police watchdog agency is investigating an arrest where a 23-year-old man suffered head injuries when Halifax police used a conducted energy weapon to subdue him.

The Serious Incident Response Team says police responded to a call Monday from a downtown restaurant alleging a man had entered their premises and stolen items from a woman's purse.

The agency says police chased the man through the city and used the conducted energy weapon after catching him.

The man fell to the ground, struck his head and lost consciousness.

Paramedics were called and the man was taken to hospital, where he has been diagnosed with serious head injuries.

The Police Act requires the director of SIRT to file a public report summarizing the result of the investigation within three months after it is finished.