Seven members of Britain's elite Royal Marines have been arrested by the Ministry of Defense on suspicion of killing an Afghan insurgent. The ministry's service justice system is investigating the allegations, The Guardian reported. The unit was set up to conduct investigations in Britain of actions by British forces elsewhere. The investigation reportedly began last month when a Royal Marine reported the alleged wrongful killing. "The Royal Military police have today arrested seven Royal Marines on suspicion of murder. The arrests relate to an incident in Afghanistan in 2011," the ministry said in a statement. "The incident followed an engagement with an insurgent: there were no civilians involved." The Royal Marines were stationed in Helmand province between April and September 2011.