A CNN Special Investigation drills down on the causes and the impact of the Fort Hood shootings, at 8 p.m. ET Saturday on CNN TV.

(CNN) -- A soldier suspected of fatally shooting 12 and wounding 31 at Fort Hood in Texas on Thursday is not dead as previously reported by the military, the base's commander said Thursday evening.

A civilian officer who was wounded in the incident shot the suspect, who is "in custody and in stable condition," Army Lt. Gen. Robert Cone told reporters.

"Preliminary reports indicate there was a single shooter that was shot multiple times at the scene," Cone said at a news conference. "However, he was not killed as previously reported."

The suspect, identified as Maj. Nidal Malik Hasan, opened fire at a military processing center at Fort Hood around 1:30 p.m., Cone said.

Three others initially taken into custody for interviews have been released, Cone said.

Hasan, 39, is a graduate of Virginia Tech and a psychiatrist licensed in Virginia who was practicing at Darnall Army Medical Center at Fort Hood, according to military and professional records. Previously, he worked at Walter Reed Army Medical Center.

A federal official said Hasan is a U.S. citizen of Jordanian descent. Military documents show that Hasan was born in Virginia and was never deployed outside the United States.

In a statement released Thursday, Hasan's cousin, Nader Hasan, said his family is "filled with grief for the families of today's victims."

"Our family loves America. We are proud of our country, and saddened by today's tragedy," the statement said. "Because this situation is still unfolding, we have nothing else that we are able to share with you at this time."

Hasan was scheduled to be deployed to Iraq "and appeared to be upset about that," Sen. Kay Bailey Hutchison, R-Texas, said.

"I think that there is a lot of investigation going on now into his background and what he was doing that was not known before," Hutchison said.

Hutchison said she was told that the soldiers at the readiness facility "were filling out paper processing to go to Iraq or Afghanistan," according to CNN affiliate KXAN in Austin, Texas.

The readiness center is one of the last stops before soldiers deploy. It is also one of the first places a soldier goes upon returning to the United States.

The base reopened Thursday night after being under lockdown for more than five hours.

At a news conference earlier in the day, Cone said at least 10 of the dead were soldiers.

The shooter had two weapons, both handguns, Cone said.

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A witness in a building adjacent to where the shooting happened said soldiers were cutting up their uniforms into homemade bandages as the wounded were brought into the building.

"It was total chaos," the witness said.

Cone said a graduation ceremony was being held in an auditorium just 50 meters from where the shooting took place.

"Thanks to the quick reaction of several soldiers, they were able to close off the doors to that auditorium where there were some 600 people inside," he said.

Peggy McCarty of Missouri told CNN affiliate KSHB that her daughter, Keara Bono, was among Thursday's wounded. She said she briefly spoke to Bono, who told her she had been shot in her left shoulder but was doing well.

"She's being deployed to Iraq on December 7," McCarty said. "I thought I was more worried about her going over to Iraq than here, just doing training in Texas. She just got there yesterday."

A woman who lives on base, about eight blocks from the shooting, said she and her daughter were at home when her husband called and told them to stay inside.

"And I asked him why, what was going on. He said that there was a shooting," said the woman, Nicole, who asked that her last name not be used. She said her husband called her back about 20 minutes later and told her to go upstairs, stay away from doors and windows and keep the doors locked.

"It's just been crazy," she said. "Sirens everywhere."

A soldier who asked not to be identified told CNN that an e-mail went out to all base personnel instructing them not to speak to the media.

President Obama called the shootings "tragic" and "a horrific outburst of violence." He expressed his condolences for the shooting victims.

"These are men and women who have made the selfless and courageous decision to risk, and at times give, their lives to protect the rest of us on a daily basis," Obama said. "It's difficult enough when we lose these brave Americans in battles overseas. It is horrifying that they should come under fire at an Army base on American soil."

Scott & White Memorial Hospital in Temple, Texas, posted an online appeal for blood as it began receving victims. "Due to the recent events on Fort Hood, we are in URGENT need of ALL blood types," it said.

Fort Hood, with about 40,000 troops, is home to the Army's 1st Cavalry Division and elements of the 4th Infantry Division, as well as the 3rd Armored Cavalry Regiment and the 13th Corps Support Command. It is located near Killeen, Texas.

The headquarters unit and three brigades of the 1st Cavalry are currently deployed in Iraq.

At least 25,000 people are at Fort Hood on any given day, an Army spokesman at the Pentagon said.

Fort Hood is home to the Warrior Combat Stress Reset Program, which is designed to help soldiers overcome combat stress issues.

In June, Fort Hood's commander, Lt. Gen. Rick Lynch, told CNN that he was trying to ease the kind of stresses soldiers face. He has pushed for soldiers working a day schedule to return home for dinner by 6 p.m., and required his personal authorization for anyone working weekends. At the time, two soldiers stationed there had committed suicide in 2009 -- a rate well below those of other posts.

Nearby Killeen was the scene of one of the most deadly shootings in American history 18 years ago when George Hennard crashed his truck into a Luby's Cafeteria and began shooting, killing 23 people and wounding 20.

Hennard's spree lasted 14 minutes. He eventually took his own life.