Capt. Robert Semrau, centre, arrives under military police escort for a custody hearing at CFB Petawawa in January. He is charged with second-degree murder in the death of a presumed enemy fighter in Afghanistan. (Tom Hanson/Canadian Press)

Court martial proceedings began Monday for a Canadian soldier charged with second-degree murder in the shooting death of a wounded Taliban insurgent in Afghanistan.

Capt. Robert Semrau is facing a military judge and five panel members on the murder charge and three other charges: attempting to commit murder, behaving in a disgraceful manner and negligently performing a military duty.

The first two weeks of the trial in Gatineau, Que., are expected to be taken up with legal arguments.

According to a joint statement by defence and prosecution lawyers. Semrau's troops were on patrol Oct. 19, 2008, when they were ambushed by Taliban insurgents in Helmand province.

His group, which included 100 Afghan National Army troops, was able to gain control. Two Taliban fighters were found: one dead, the other severely wounded.

The insurgent casualty was wounded too severely for any treatment in the field, the statement says.

Semrau was left alone with the injured man and two shots were heard, according to the statement. The statement claims an unnamed witness interviewed by military investigators will testify he saw Semrau shoot the man.

The body was left behind and not recovered.

Semrau had served three years with the British army, including deployments in Macedonia and Afghanistan, according to documents presented at his hearing.

He left with an "exemplary discharge" and joined the Canadian Forces in 2005, where his record was unblemished until the charges were laid.