On 23 December, an investigation was started to the deaths of Lance Corporal Michael David Pritchard, aged 22, a member of the Royal Military Police who was attached to 3rd Battalion The Rifles, and Lance Corporal Christopher Roney aged 23, from 3rd Battalion the Rifles, who possibly died as a result of friendly fire ("blue on blue"), the last one after a vicious firefight in Patrol Base Almas near Sangin in Helmand. This brought the number of British service personnel deaths in Afghanistan in 2009 to 106. There had been 243 British troops killed in Afghanistan since 2001.