03/08/2012 07:26 EST | Updated 05/08/2012 05:12 EDT

Accused ex-Mountie admits to killing Ottawa police officer

A former Mountie accused of slaying an Ottawa police officer testified in his own defence Thursday, admitting that he killed Const. Eric Czapnik but did not "murder" him.

Kevin Gregson, 45, is charged with first-degree murder in the death of 51-year-old Czapnik, who was stabbed outside the Civic Campus of the Ottawa Hospital in the early morning of Dec. 29, 2009.

Gregson is also charged with robbery in relation to a carjacking the night before the stabbing. He has pleaded not guilty to both charges.

Defence lawyers began presenting their case in front of a full courtroom after seven days of testimony from Crown witnesses. Lawyers Craig Fleming and François Dulude sent Gregson to the witness box immediately.

During rambling testimony, the accused said, "Eric Czapnik, the police officer I killed, he was a good man. I killed him, I didn't murder him."

'Never really wanted to become a cop'

Gregson talked about his past, including his time at Merivale High School in Ottawa, as well as his first marriage and a couple of jobs. He then spoke about his career in police work.

"I never really wanted to become a cop, but I needed a job," he told the court.

Gregson also said he became more violent while working at the Royal Ottawa Hospital, a mental health facility. He said he "could thump people pretty good" there and went into policing to create "order."

His "aboriginal ticket", he told the court, helped him become an RCMP officer in 1997-98. Gregson then described training in an air marshal course where he learned to use a knife to attack the neck.

The former Mountie said he was officially part of the force almost a year after Czapnik's death. He said he received his termination papers in late 2010 while in jail.

Gregson blamed failed suicide attempts for stabbing

Proceedings have progressed faster than expected because Gregson's lawyers have not spent much time cross-examining the witnesses. The trial was expected to last a month.

The defence has also not disputed that Gregson stabbed Czapnik, and in this case, premeditation or planning does not influence the charge because killing a police officer is automatically deemed first-degree murder.

In a three-hour police interrogation videotaped hours after he was arrested, Gregson told Sgt. Tim Hodgins he was suicidal.

He said he wanted a gun to commit suicide because his attempts with a knife were not working. He also told Hodgins he would use the Mental Health Act as a defence.

Two Crown witnesses, who are experts of the brain and studied Gregson's neurological makeup the night of Czapnik's death, testified Wednesday there was no sign of major brain problems.

Gregson had been diagnosed with a brain condition called hydrocephalus in 2006, but a shunt had been inserted and the court was told that solved any major issues.

Dr. John Sinclair told the court hydrocephalus does not cause increased aggression. It causes confusion headaches, nausea, drowsiness and can cause death.

The defence argued the shunt irritated Gregson and the brain injury did impact him as an RCMP officer in Saskatchewan.

Gregson spent almost three hours on the stand and returns there Friday morning for cross-examination from the Crown. The court adjourned early.