KANDAHAR, Afghanistan - The shooting death of Afghan President Hamid Karzai's cousin was a tragic accident, but the overnight raid during which it occurred was justifiable because it netted a Taliban leader responsible for car bombs in Kandahar city, an American military commander said Sunday.

Hours after he took command of the Kandahar district of Dand -- a region within Canada's area of operations -- Lt.-Col. Douglas Sims said the military regrets last week's fatal shooting of Yar Muhammad Karzai.

"Naturally, any loss of life is tragic and this loss certainly was no less tragic," Sims told The Canadian Press.

"While we are certainly regretful for the loss of life, I think that the Afghan government here clearly understands that this was a legitimate action. There was a pretty bad character that was involved in this."

The 63-year-old was killed in the village of Karz during an operation Wednesday night by NATO troops in Dand, a relatively stable district south of Kandahar city.

During the raid, troops detained five people including a Taliban leader responsible for distributing vehicle-borne improvised explosive devices -- more commonly known as car bombs -- to insurgents throughout the city. The four others were later released.

Sims said capturing a leader like that is a major step towards improving security in the area, adding that he is confident local government officials recognize that.

"Although the accident occurred, I think they recognized that in the end, security was enhanced," Sims said.

But Karzai's younger brother, who lives in Toronto and is a sociology professor for Laurentian University, dismissed Sims's statement and called on the Canadian military to conduct its own investigation into the raid.

"Given the resources invested in this war, it is not absurd to expect that a Canadian commander could easily track down who requested and authorized this raid and why," Anas Karzai said in an email.

"What appears to be missing is the will."

The Canadian military deferred to the findings of the NATO investigation into Karzai's death.

NATO said troops initially believed Karzai was the father of the detained Taliban leader. Security forces shot him when a soldier saw "an armed individual pointing an AK-47 with a flashlight" through a window in a compound where the operation took place, said Regional Command South, which oversees NATO operations in southern Afghanistan.

"The security force member assessed the male as an immediate threat to the security force, and engaged him with precision small arms and killed him," they said in a statement Sunday after concluding its investigation.

Sims, who leads the 1st squadron of the 2nd Stryker Regiment, took the reins of the Dand battle space from the 1-71 Cavalry of 10th Mountain Division. The 500-member U.S. cavalry has been stationed alongside Afghan National Security Forces and a small number of Canadian troops since May.

Relations between the Afghan president and NATO have been strained in recent weeks because of civilian shooting deaths. But Sims said he was not worried that Karzai's death would undermine counterinsurgency progress in Dand.

"The atmosphere out here is not one of animosity," he said.

The 700-member Stryker squadron Sims leads came from a 10-month tour in the province of Uruzgan, which sits on the northern border of Kandahar province. It falls under the command of Brig.-Gen. Dean Milner, Canada's top soldier in Afghanistan.

Two companies of soldiers will go to Dand and a third will be deployed to the neighbouring district of Panjwaii, a more volatile area.

Sims said he believes Taliban members have probably started trickling into the area and that he anticipates a spike in violence next month.

"So we're here at a pretty important time and I think the fact that we've been fighting the Taliban for 10 months (in Uruzgan), we come into Dand with a pretty strong understanding of the enemy."

Lt.-Col. John Paganini, who commands the 1-71 Cavalry, said the main goal for Sims will be to prevent the Taliban from attempting to divide the locals from their government.

"The most important thing that he will do in the period that he's here will be maintaining the relationship between the population and their government and the population and their security force," Paganini said last month.

"What's going to make this fighting season significant is the population looking at the enemy and saying, 'You can't come here this year.' And the conditions are set for that."

The transfer of command ceremony Sunday is one of the last before Canada's combat mission in Afghanistan winds down in July.