Robert Semrau has been demoted and also dismissed from the Canadian Forces as punishment after he was convicted of disgraceful conduct in the shooting of an unarmed Afghan insurgent.

Military judge Lt.-Col. Jean-Guy Perron demoted Semrau from captain to second-lieutenant when handing down his sentence in a Gatineau, Que., courtroom on Tuesday morning.

"If you are committing a disgraceful conduct you cannot maintain that rank of leadership, which is the rank of captain," said Lt.-Col. Bruce MacGregor, director of military justice policy for the Canadian Forces.

Earlier this year, Semrau, 36, was convicted of disgraceful conduct in the October 2008 shooting of an unarmed enemy fighter who had been mortally wounded in Afghanistan.

At the time of the incident, Semrau had been on a mission with Afghan and Canadian soldiers to clear out Taliban insurgents from a part of Helmand province.

The soldiers came under attack and when the fighting stopped, one insurgent was killed and another was severely wounded.

Witnesses later said that after the fighting ended, Semrau returned to the site of the fighting with a Canadian soldier and an Afghan soldier and twice shot the wounded fighter at close range to put him out of his misery.

According to what the Canadian witness told Semrau's trial, the Canadian Forces captain said "it would be inhumane to leave (the wounded insurgent) like that, he was mortally wounded," said CTV's Daniele Hamamdjian when discussing the case on CTV News Channel on Tuesday morning.

Witnesses said the wounded insurgent whom Semrau shot had been strafed by a helicopter and had suffered a severed leg in the fighting.

The road to sentencing

Three months after the incident, Semrau was charged with second-degree murder, but he was acquitted of that charge at trial. Instead, he was found guilty of disgraceful conduct.

Semrau did not testify during his months-long trial, which wrapped up in July.

The judge told Semrau at his sentencing that his conduct on the battlefield had been "shockingly unacceptable."

"Your actions might have been motivated by honest belief you were doing the right thing," Perron said. "Nonetheless, you committed a serious breach of discipline."

Perron also told Semrau that he had set a poor example for his own troops.

Semrau sat quietly in the courtroom as Perron handed down his sentence during the hour-long hearing.

Perron said the case involving Semrau and the shooting of the unarmed insurgent was "unique," with no similar cases in existence.

The judge said the shooting was "completely out of character" for Semrau, but was also done without regard for the rules of the military.

Perron said Semrau would be dismissed from the military without disgrace, meaning that he could work for the Crown or the government in future. He did not order Semrau to serve any jail time.

Defence lawyer, Capt. David Hodson, said Semrau was "very disappointed" with the sentence.

"He's a warrior, he'd love to be serving the Canadian Forces and serving his country," Hodson told reporters outside the courtoom. Hodson said they are considering an appeal.

Experts say the sentence is harsh, but appropriate.

"It fits the crime and no more than the crime," said retired colonel Michel Drapeau.

Prior to his military trial, Semrau had a spotless record with the Canadian military.

With files from The Canadian Press