fn571Washington DC- A 5.7 millimeter pistol was identified Friday as the weapon used by Nidal M. Hasan in the Fort Hood shooting. The pistol was legally purchased by suspect Nidal Hasan at a Texas gun shop, said law enforcement officials on Friday.

The killer shot dead 13 people at Fort Hood using this FN 5.7 millimeter pistol, “an assault rifle that fits in your pocket”. The weapon is mainly used by Mexican drug cartels.

Initial report said twelve people lost their lives in the macabre killing. But now the toll reaches 13 while the number of injured person is 31.

Presiden Obama has ordered the United States’ flag to be flown at half staff. He has expressed his grief over the gruesome killing of innocent people.

Hundreds of people have condemn the death and expressed their sympathy with the bereaved families.

Though the type of ammunition used in Thursday’s attack was not immediately known, investigators and news reports confirmed that the most powerful type of ammunition for the FN 5.7 gun is available only to law enforcement and military personnel. Gun control advocates call it a “cop killer” weapon because that ammo can pierce bulletproof vests.

Agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives, as well as the Texas Rangers have interviewed store personnel about Hasan’s gun purchase. One official said the store records do not indicate Hasan purchased any ammo when he bought the gun.