Officials: Oregon Shooter Was Discharged From Army After a Month, Had 13 Weapons

The 26-year-old man who opened fire in a Oregon college, killing nine and wounding at least seven others, had an arsenal of weapons in his possession and in his home at the time of the massacre, officials said Friday.

Police recovered six weapons belonging to Chris Harper-Mercer at Umpqua Community College in Roseburg, said Celinez Nunez, an assistant special agent  with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF).

Read: Train Hero Alek Skarlatos Would Have Been At Oregon College if He Hadn't Been on DWTS

A flak jacket with steel plates was also found lying next to a rifle and five magazines in the school, Nunez said. 

Investigators also found seven weapons— one shotgun, two pistols and four rifles— as well as additional ammunition at Harper-Mercer's home, officials said.

All of the weapons were purchased legally by either Harper-Mercer or a family member from a federal gun dealer.

Read: Trevor Noah on Oregon Mass Shooting: 'This Is Not A Normal Situation For Me'

The number of weapons Harper-Mercer owned is not uncommon for the area, Douglas County Sheriff John Hanlin said.

"In Oregon, this is a hunting state and firearms are possible in most households," he said.

Officials also confirmed that Harper-Mercer spent a short period of time serving in the U.S. Army. 

"A review of Army records indicate that Christopher Sean Harper-Mercer was in service at Ft Jackson, S.C.," Lt. Col. Ben Garrett, an Army spokesman said in an email to INSIDE EDITION.

Harper-Mercer served from November 5 to December 8, 2011 before being discharged for failing to meet the minimum administrative standards to serve in the U.S. Army, Garrett said.

The standards Harper-Mercer failed to meet were not revealed. 

 Watch Below: Oregon College Gunman's Dad: 'I'm Just as Shocked As Anybody'