The U.K. is facing a legal challenge over its possible role in providing information used in the U.S. "kill list" in Afghanistan.

The challenge to Britain's Serious Organized Crime Agency (SOCA) and the Ministry of Defense is brought by Habib Rahman, who lost five family members -- two brothers, two uncles and his father-in-law -- in a missile attack in September 2010, which International Security Assistance Force says was a "precision air strike" that killed "insurgents" but investigation by Afghanistan Analysts Network shows was a case of mistaken identity.

Rosa Curling of Leigh Day & Co, a British firm representing Rahman, said, "Our client's case suggests that the establishment and maintenance of the 'killing list' is not in line with the UK's duties under international humanitarian law.

"It is important that the MoD and SOCA provide us with the reassurances sought, to make sure that others do not suffer the tragic loss of life as experienced by Mr Rahman."

The Guardian adds that "who is put on the 'kill list' and why remains a closely guarded secret – and has become a huge concern for human rights groups. They have questioned the legality of such operations and said civilians are often killed."

A 2009 report to the US Senate's committee on foreign relations stated, "The military places no restrictions on the use of force with these selected targets, which means they can be killed or captured on the battlefield."