Officials say a 13th person has died after a gunman opened fire yesterday afternoon at Texas' Fort Hood. 28 people are still in the hospital.

In a live news conference Friday morning, Ft. Hood officials confirmed that one of the victims is a civilian. The other 12 are military personnel.

Maj. Nidal Malik Hasan, the suspected shooter, is on a ventilator and unconscious after being shot four times. In the early chaos of the shooting, authorities believed they had killed the shooter.

Authorities said immediately after Thursday's attack that they had killed the suspected shooter. But officials now says the suspected shooter is alive and in stable condition.

A senior U.S. official is offering more insight into why authorities initially claimed the suspected shooter was dead. The official says authorities thought one of the 12 victims in yesterday's rampage was the shooter. The mistake meant it took several hours before authorities identified Army psychiatrist Maj. Nidal Malik Hasan as the gunman. Hasan was shot four times, but survived.

Two others possible suspects were apprehended initially but have since been released. The FBI is now involved in the investigation.

An Army spokesman at the Pentagon says the shootings began about 1:30 p.m. Thursday at a personnel and medical processing center at Fort Hood.

Lt. Gen Bob Cone at Fort Hood said Thursday that all the casualties took place at the base's Soldier Readiness Center where soldiers who are about to be deployed or who are returning undergo medical screening.

There is no word yet on the identities of the dead.

Cone says it is too soon to tell whether there is any link to battle stress or repeated deployments. The Army is suffering a record high suicide rate and other signs of stress from fighting two wars.

There are also confirmed reports that a police officer was shot in a post exchange, but other details weren’t available.

In a story carried by KKTV's CBS affiliate in Waco, it quotes CNN reporting that the president was advised of the shootings at about 2:45 p.m. Thursday.

All available ambulances and paramedics in the area were responding to post.

The shooting happened on Battalion Avenue.

Fort Hood is shut down and no one is being allowed on or off post.

Killeen ISD officials say all nine schools on post are on lock down because of the situation.

Students at those schools were to have been released early, but parents are being advised they cannot yet pick up children.

Fort Hood is in Killeen, Texas, between Austin and Waco.

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