At least four people were killed Wednesday, including the alleged attacker, and 16 others were injured in a shooting at the Fort Hood military base in Texas, one of the largest in the United States. In 2009 Fort Hood also experienced a similar massacre when Army psychiatrist, Nidal Hasan began shooting, leaving 13 dead and 30 wounded.

The suspect in the shooting, who ended up committing suicide, has been identified as Iván López, he was 34 years old, and was a soldier that had served four months in the Iraq war in 2011 and was taking medication for depression, anxiety and other psychiatric disorders probably linked to his war experience, Lieutenant Mark Milley said at press conference.

The military authorities of the base have not seen evidence of terrorism in the incident, but do not rule out any hypothesis or have determined by now no clear reason to explain what happened.

All the victims were military personnel and in the early hours of Thursday, all the hospitalized injured had a serious diagnosis. Three of them are in a critical state, informed doctors of Scott & White Healthcare.

According to Milley, doctors were in the process of diagnosing the attacker with post-traumatic stress disorder (PTSD), a medical condition that has affected more than 250,000 Americans upon their return home from the wars in Iraq and Afghanistan.

The attacker entered a building and opened fire, after which he returned to his vehicle, fired more shots from the car and then returned to shoot at another building in the compound. Lpoez ended up shooting himself upon encountering agents of the military police, said Milley.

The weapon used was a 45 caliber semiautomatic hand pistol that was not registered, as required by the military base, said lieutenant general.

The perpetrator arrived at Fort Hood last February, coming from another U.S. military installation, so Texas authorities knew little about him.