Capt. Robert Semrau, shown in here in October preparing to go to battle, has been charged with second-degree murder in relation to the shooting death of a man in Afghanistan. (CBC)

A captain with the Canadian Forces has been charged in connection with the death of a presumed insurgent in Afghanistan's Helmand province.

Robert Semrau, originally from Pembroke, Ont., was charged with one count of second-degree murder on Wednesday, military officials said Friday in a news release.

Semrau is accused of shooting a man with the intent to kill. The man is alleged to have been unarmed at the time of his death, according to a Canadian Forces press release.

Semrau is being held in military police custody in Afghanistan, and is expected to be returned to Canada for a hearing before a military judge. If convicted, he faces 25 years in prison.

Officials said they will not be commenting further because part of the investigation is ongoing.

Canadian soldiers were mentoring Afghan soldiers in Helmand province at the time of the death in October.

That month, Afghan soldiers were defending the Helmand capital, Lashkar Gah, from a prolonged attack by insurgents. The soldiers were being supervised by Canadian military mentors with NATO's Operational Mentoring and Liaison Team, and were backed up by British forces.

Prepared for battle

In a taped video interview with Semrau filmed in October for the Digital Video and Imagery Distribution System, a U.S.-army run website that publishes military-related audio-visual materials, he said the Canadian OMLT soldiers were preparing to go into Lashkar Gah for an operation with the Afghan army.

Semrau said he was looking forward to going south for the battle.

"It beats sitting in the barracks, thumb up bum. It's a lot more fun doing the job," he said.

Semrau said the Canadian members of the OMLT had been working with the Afghan National Army for about a month and a half at the time.

They're "really good guys — motivated," he said. "They're well into it, so we're going to have a good go."

The Canadians on the OMLT, who come from the 1st and 2nd Battalion of the Royal Canadian Regiment, have been operating with the mentoring team since August. The program embeds small groups of soldiers with the Afghan army for a period of about six months.

Semrau was a commanding officer in the OMLT.

Afghan and NATO officials have previously stated that about 100 Taliban died during the fighting in Lashkar Gah.

Afghan Gen. Sher Muhammad Zazai has acknowledged Canadians were involved in fighting in Helmand, which began on Oct. 16.

The battle, which also involved air strikes, ended Oct. 18.

So many Taliban fighters died during the defence of the capital that it is impossible to say how they all died, Zazai said.

But military officials have said the death of the man allegedly happened "on or about" Oct. 19 in Helmand.

Probe announced earlier this week

The investigative arm of the Canadian Forces announced on Wednesday that it was probing possible inappropriate conduct stemming from the death of a presumed insurgent.

Canadian military officials were made aware of the allegations on Dec. 27, and notified the Canadian Forces National Investigation Service (CFNIS), which immediately began an investigation.

The probe was meant to investigate whether "proper reporting procedures were followed," said Col. Jamie Cade, acting commander of Task Force Afghanistan.

Charges were laid after analyzing evidence and interviewing witnesses, according to the Canadian Forces press release.

The CFNIS is an independent military police unit with a mandate to investigate serious and sensitive matters in relation to national defence, property, departmental employees and Canadian Forces personnel serving in Canada and abroad.

Canada has about 2,500 soldiers in Afghanistan, mostly based in the south around Kandahar. Neighbouring Helmand province is largely patrolled by British troops.