The communists killed most of them. You liberals always blame our enemies sins on the US.

According to the Vietnamese government, there were 1,100,000 North Vietnamese Army and Viet Cong military personnel deaths during the Vietnam War (including the missing).[48] Rummel reviewed the many casualty data sets, and this number is in keeping with his mid-level estimate of 1,011,000 North Vietnamese combatant deaths.[49] The official US Department of Defense figure was 950,765 communist forces killed in Vietnam from 1965 to 1974. Defense Department officials believed that these body count figures need to be deflated by 30 percent. In addition, Guenter Lewy assumes that one-third of the reported "enemy" killed may have been civilians, concluding that the actual number of deaths of communist military forces was probably closer to 444,000.[46]

The Army of the Republic of Vietnam suffered 254,256 recorded deaths between 1960 and 1974, with the highest number of recorded deaths being in 1972, with 39,587 combat deaths.[45] According to Lewy, ARVN suffered between 171,331 and 220,357 deaths during the war.[46][47] R.J. Rummel estimated that ARVN lost between 219,000 and 313,000 deaths during the war.[20]