(Photo of suspected shooter, courtesy of Glidden Lopez)
(Family photo)

UPDATE: For our latest story on the gunman, head here.

The gunman who opened fire at Fort Hood, Tex., was an Iraq war veteran dealing with mental health issues; he “had a clean record,” according to the secretary of the Army; and he was considered “low risk.”

We know certain things about the gunman. But as we enter the first full day after the shooting that left four people dead (including the gunman) and injured 16 people, there is still a lot we don’t know, so remember that we’re expecting a lot more information to emerge in the hours and days ahead.

Army Spec. Ivan Lopez, 34, has been identified by officials as the gunman.

He “had a clean record” with no major misbehavior appearing yet, Secretary of the Army John M. McHugh said in an appearance before the Senate Armed Services Committee Thursday morning.

Lopez had served two deployments, including one in Iraq from August to December 2011, but did not have direct involvement in combat.

“He was undergoing a variety of treatment and diagnoses for mental health conditions ranging from depression to anxiety to some sleep disturbance,” McHugh said.

He was examined by a psychiatrist last month, and there were no indications ““that there was any sign of likely violence to himself or others,” according to McHugh.

Background checks so far have shown no involvement with any extremist organizations, McHugh said.

The gun he used on Wednesday — a .45 caliber Smith & Wesson semiautomatic pistol — was purchased recently at the same gun store where Nidal Hasan bought the gun used in his 2009 shooting at the post.

Lopez grew up in the town of Guayanilla, on Puerto Rico’s southwest side. He was “quiet…introverted, calm,” Edgardo Arlequín, the town’s current mayor, told The Washington Post in a telephone interview Thursday. Lopez never seemed to get angry or get into a fight, but he did have a clear talent as a musician, Arlequín said.

Lopez was considered a “low risk” soldier at Fort Bliss’s 1st Armored Division, 4th Brigade, where he spent two years as an infantryman until November 2013, according to a person familiar with his military service. His commanders at Fort Bliss, his first active duty base, didn’t know he was taking any medication for depression or anxiety due to privacy regulations, but he had no behavior problems that raised red flags.

However, he had gone through some levels of stress. His mother died in the last year, and he had been seeing a chaplain for counseling related to that and other unknown issues. He left Fort Bliss in November for several months of training to become a truck driver, then won an assignment with a truck-driving unit at Fort Hood beginning in February.

Lopez spent a decade as a police officer in Puerto Rico. He also spent nine years in the Puerto Rico National Guard, Gen. Ray Odierno, the Army chief of staff, told the Senate Armed Services Committee Thursday morning.

He lived in an apartment in Killeen, a city near Fort Hood, rather than on the post.

This post was originally published at 12:02 p.m. Last update: 2:46 p.m.

David A. Fahrenthold and Carol D. Leonnig contributed to this report.