Update, 6:30 p.m. Thursday: Listen to KERA's interview with a survivor of the 2009 Fort Hood shootings, retired Staff Sgt. Alonzo Lunsford.
A soldier opened fire Wednesday on fellow service members at the Fort Hood military base, killing three people and wounding 16 before committing suicide.
The incident took place at the same Army post where more than a dozen people were killed in a 2009 attack.
The shooter, who served in Iraq in 2011, has been identified by NPR as Spc. Ivan Lopez, a 34-year-old military truck driver. The man had mental health issues and was being evaluated for depression and post-traumatic stress disorder, according to Lt. Gen. Mark A. Milley, the senior officer on the base.
We're updating this post throughout the day. Check with NPR for the latest developments, too.
4:15 p.m. Thursday update: Gunman bought .45-calber pistol in Killeen March
Milley said Thursday that Lopez purchased a .45-caliber pistol from Guns Galore, a store in Killeen, on March 1.
The Associated Press reports that Guns Galore is where Nidal Hasan bought the gun he used to kill 13 people in the earlier Fort Hood rampage in 2009.
NPR reports: Milley identified the shooter as Spc. Ivan A. Lopez, 34, originally of Puerto Rico. He said there was "strong evidence of a medical history that indicated an unstable psychological condition."
Lopez belonged to the 49th Transportation Battalion at Fort Hood, but had transferred from Fort Bliss in El Paso.
Milley said there was a "strong possibility that a verbal altercation with another soldier or soldiers preceded the shootings," but no indication that Lopez targeted specific individuals.
He said four of the 16 wounded had been released from the hospital.
1:57 p.m. update: Red Cross seeking donations
KUT in Austin reports: "Fort Hood soldiers and civilian workers are expected to report to work today, although physical training has been canceled. The Killeen Independent School District is holding classes as usual. KISD operates all schools on post.
"The Red Cross has set up at the Killeen Community Center and will be coordinating support. The Red Cross says they currently have enough blood supply to meet the need. Monetary donations can be made online at redcross.org."
1:45 p.m. update: Texas' Crime Victim Services Division heads to Fort Hood
Texas Attorney General Greg Abbott is sending members of his Crime Victim Services Division to Fort Hood to work with victims of Wednesday’s attack. The division will be assisting in victim applications for the Crime Victims’ Compensation Fund. The Crime Victims' Compensation Program reimburses out-of-pocket expenses to victims of violent crime and their families.
Abbott said in a statement: “Our hearts break for the wounded military men and women and the families of those who died. Few answers can be found in the days immediately after such a tragedy, but we pledge to assist in any we can. Members of our military and Texans in the Fort Hood-area have stared down adversity before, and they will do it again.”
1:35 p.m. update: Disaster Distress Helpline offers counseling
The Disaster Distress Helpline at 1-800-985-5990 offers counseling to anyone who needs help in dealing with the Fort Hood shooting. The helpline, sponsored by the Substance Abuse and Mental Health Services Administration, is open 24 hours a day, seven days a week and provides crisis counseling after a natural disaster or tragedy. Helpline staffers provide confidential counseling, referrals and other needed support services.
12:15 p.m. update: Authorities search gunman's home
Investigators are searching the home and questioning the wife of the gunman. Fort Hood spokesman Chris Haug says the shooter lived with his wife and children locally after transferring from another military installation in Texas in February, The Associated Press reports. The shooter, identified as Ivan Lopez, killed three and injured 16 on Wednesday before turning his privately owned .45-caliber handgun on himself.
Suzie Miller, a 71-year-old retired property manager who lived in the same apartment complex as Lopez near Fort Hood in Killeen, said few in the area knew him and his wife well because they had just moved in a few weeks ago.
"I'd see him in his uniform heading out to the car every morning," Miller told the AP. "He was friendly to me and a lot of us around here."
11 a.m. update: Gunman was examined by a psychiatrist
Army Secretary John McHugh said the gunman was seen last month by a psychiatrist.
"He was fully examined and as of this morning we had no indication [from] the record of that examination that there was any sign of likely violence either to himself or to others," McHugh said. He was testifying at a previously scheduled Senate hearing.
The gunman "had a clean record" in the military, and background checks of him "show no involvement with extremist organizations of any kind," McHugh said.
McHugh also told lawmakers that the soldier had been prescribed multiple prescription drugs, including a sleep aid.
10:55 a.m. update: The gunman's background
Gen. Ray Odierno, the Army's chief of staff, said the gunman had been in the Puerto Rico National Guard for nine years before joining the U.S. Army.
"Lopez was from the U.S. territory of Puerto Rico and joined the island's National Guard in 1999," The Associated Press reports. He went on a peace and security mission to Egypt's Sinai Peninsula in the mid-2000s, and left the National Guard in 2010 to join the U.S. Army, said Lt. Col. Ruth Diaz, spokeswoman for the Puerto Rico National Guard.
10:50 a.m. update: Patients recovering
The injured were taken to Darnall Army Community Hospital at Fort Hood and other local hospitals.
At Scott and White Hospital in Temple, hospital officials gave an update on the patients Thursday morning. Nine shooting victims were at the hospital -- three remain in critical condition. Two are in fair condition. Four are in good condition. Several of those could be sent home today. Those who are awake are in good spirits, hospital officials said at the press conference. Of the patents in critical condition, one has a neck injury; one has a potential spine injury and one has an abdominal injury. But no more fatalities are expected, the hospital said.
From Wednesday night: How it happened
There was no indication the attack was related to terrorism.
The gunman arrived on the post carrying a semi-automatic .45 caliber pistol. He opened fire on one building and then got into a car, where he fired more shots. He then entered another building and shot again.
Eventually, a military police officer cornered him in a parking lot and that's where he shot himself in the head, Milley said.
As hospitals treat the wounded, relatives worry
The post was locked down after the shooting began. Hours later, all-clear sirens sounded.
For relatives of soldiers, it was a nerve-racking night as they waited for news about their loved ones.
Tayra DeHart, 33, said she had last heard from her husband, a soldier at the post, that he was safe, but that was hours earlier.
"The last two hours have been the most nerve-racking I've ever felt. I know God is here protecting me and all the soldiers, but I have my phone in my hand just hoping it will ring and it will be my husband," DeHart said.
Brooke Conover, called her husband, Staff Sgt. Sean Conover, to make sure he was OK, but he could not even tell her exactly what was going on, only that the base was locked down.
"I just want him to come home," said Conover, who moved to Fort Hood with her husband and three daughters two years ago.
The president reacts
President Barack Obama vowed that investigators would get to the bottom of the shooting. He said the shooting brought back painful memories of the 2009 Fort Hood killings, which was the deadliest attack on a domestic military installation in U.S. history. Thirteen people were killed and more than 30 wounded in 2009.
Obama reflected on the sacrifices that troops stationed at Fort Hood have made - including enduring multiple tours to Iraq and Afghanistan.
"They serve with valor. They serve with distinction, and when they're at their home base, they need to feel safe," Obama said. "We don't yet know what happened tonight, but obviously that sense of safety has been broken once again."
Texas Gov. Rick Perry said in a statement: “Today, Fort Hood was once again stricken by tragedy. As Texans, our first priority must be caring for the victims and their families.”
U.S. Sen. John Cornyn said: “Tonight, Texans’ hearts are once again very heavy. The scenes coming from Ft. Hood today are sadly too familiar and still too fresh in our memories. No community should have to go through this horrific violence once, let alone twice. I ask that all Americans join Sandy and me in praying for the victims, their families and the entire Ft. Hood community.”
“Stay away from windows”
Shortly after reports of a shooting Wednesday afternoon, the 1st Cavalry Division posted a note on Twitter that personnel "should shelter in place immediately, close doors and stay away from windows."
This video shows the alert being broadcast throughout Fort Hood:
Eyewitnesses told local news stations they saw a stream of emergency vehicles make their way onto the post. One witness said he saw police escort service members and civilians from buildings with their hands in the air.
We’ve compiled this story based on reporting from The Associated Press, NPR and KUT, Austin’s public radio station.