The neighbor, Patricia Villa, said Maj. Nidal Malik Hasan came over to her apartment Wednesday and Thursday and offered her some items, including a new Quran, saying he was going to be deployed on Friday. She wasn't sure if he was going to Iraq or Afghanistan.

Authorities said Hasan went on a shooting spree later Thursday at the sprawling Texas post. He was among 30 people wounded in the spree and remained hospitalized on a ventilator Friday. All but two of the injured were still hospitalized, and all were in stable condition.

Investigators were still trying to piecing together how and why an Army psychiatrist facing deployment allegedly gunned down his comrades in one of the worst mass shootings ever on an American military installation.

"This was an individual who took it upon himself to attack and murder his colleagues, people who were on the base with him," Homeland Security Secretary Janet Napolitano told Sky News from Brussels. "That investigation is underway by law enforcement authorities, and let's let that be the No. 1 priorty in terms of ascertaining what motivations he had."

An imam from a mosque Hasan regularly attended said Hasan, a lifelong Muslim, was a committed soldier, gave no sign of extremist beliefs and regularly wore his uniform at prayers.

Soldiers who witnessed the rampage reported that the gunman shouted "Allahu Akbar!" — an Arabic phrase for "God is great!" — before opening fire, said Lt. Gen. Robert Cone, the installation commander. He said officials had not yet confirmed that Hasan made the comment before the shooting spree.

Villa, who recently moved next door to Hasan, said she had never spoken to him before he came over to her apartment.

She said Hasan gave her frozen broccoli, spinach, T-shirts and shelves on Wednesday, then returned Thursday morning and gave her his air mattress, several briefcases and a desk lamp.

He then offered her $60 to clean his apartment Friday morning, after he was supposed to leave.

Enlarge By LM Otero, AP Agent stands in the door of the apartment of Maj. Nidal Malik Hasan in Killeen, Texas, early Friday.