Glen Race pleaded guilty in September to second-degree murder in Michael Knott's death and first-degree murder for killing Trevor Brewster. (CBC)

Glen Race, who was at the centre of an international manhunt after killing three men, has been found not criminally responsible for killing Michael Knott and Trevor Brewster in May 2007.

Race pleaded guilty in September to second-degree murder in Knott's death and first-degree murder for killing Brewster.

While he admitted to the crimes, Race's lawyer argued he should be found not criminally responsible in the fatal stabbings because of mental illness. 

In November, three forensic psychiatrists testified about Race's mental state at the time of the crimes. Justice Kevin Coady decided to accept the conclusions from the expert medical evidence.

The case has been complicated by the amount of planning Race demonstrated both before and after the killings. Court heard Race stabbed Knott to death after meeting him on Citadel Hill on May 1, 2007. He dumped Knott's body in Mill Cove, a remote spot west of Halifax, and disposed of his car near the airport.

Seven days later, Race attacked Brewster in a Dartmouth park. He concealed the body under a boardwalk at a lake, then took off in Brewster's car.

Race drove the car to Quebec before he concealed it on a remote road and sneaked across the border into New York state. There, Race killed a third man — Darcy Manor — and stole his pickup truck.

Race drove Manor's truck south, stealing licence plates along the way to make the truck harder to track. He made it to within a few metres of the Mexican border before being caught.

The three forensic psychiatrists testified that despite all the planning Race demonstrated before and after each killing, his delusional mental state means he should not be held criminally responsible.

Court heard Race believed he was a godlike entity ordered by angels to cleanse the world of sin by killing vampires, demons and, eventually, everyone on the planet.

Race has already been convicted of murder and sentenced to life in prison in the United States for Manor's murder. He was extradited from the U.S. in October 2010 to face the murder charges in Halifax.

RCMP Sgt. Al LeBlanc confirmed that Race was put on a plane back to New York state to serve out the balance of his life sentence at Attica Correctional Facility.

Joel Pink, Race's Canadian lawyer, is trying to get an American court to hear an appeal of his conviction and sentence there.

With files from The Canadian Press