A Tyngsboro native stationed at Fort Hood said today he was stunned to learn fellow serviceman Maj. Nidal Malik Hasan opened fire at the Texas base yesterday killing 12 and wounding 31 people.

“The biggest shock was finding out his rank and what he did for the Army,” said Sgt. Timothy Dunbar, 28, who works for command staff at the base. “I was just completely lost for words.”

Dunbar, a 1999 Tyngsboro High School graduate, said he had just left a USO event in Dallas with Brig. Gen. William Grimsley when the second-in-command at Fort Hood was delivered the news about the shooting rampage. He called his father, Thomas, at work to let him know he was in Dallas and OK.

“I didn’t know 100 percent everything that was going on,” said Dunbar, who drove Grimsley and his wife 170 miles back to the base. “The numbers kept growing as we were coming back. We had to get him on post. It was treated like terrorist attack.”

Dunbar said vehicles were backed up on the roads approaching the base because no one was permitted to enter or leave Fort Hood. Dunbar said he was given permission to pass because Grimsley was in the vehicle.

“There was nothing but cars backed up for miles,” said Dunbar, who described the scene as “eerie.”

He said the commanding officers had to sort through a lot of conflicting reports and speculation to get their facts straight.

“It was a pretty chaotic event,” said Dunbar. “They were trying to get all the facts in order. There was a lot of speculation.”

Dunbar lives on the base with his wife, Christine, and four children, ages 2, 3, 5, and 8, who are all safe. He said he does not know yet whether he knows any of the victims. Dunbar said he will serve as a driver for high-ranking command staff today, but could not give more details.

The Soldier Readiness Center where the assault occurred is one the busiest sites on the Army post because all soldiers preparing to deploy or returning from a deployment have appointments there, Dunbar said. A graduation was also held there yesterday, he said.

Lynn Murray, of Sudbury, said she was relieved because her son, Brad, 21, was 20 kilometers away from the post for a multi-day training yesterday.

Brad Murray is an Army private first class assigned to the 3d Armored Cavalry Regiment. He lives there with his wife, Crystal, who is a nursing student.

“Believe me I breathed a huge sigh of relief,” said Lynn Murray, who visited the post with her husband, Dan, two weeks ago. “I was very upset by this. He could have easily or his wife could have easily been in that spot. I thanked God he was safe.”

Murray said she hasn’t spoken to her son yet, but has been in touch with her daughter-in-law and got e-mail updates from the Family Readiness Group.

“It’s going to be so good to hear his voice,” she said. “My heart just weeps for the other moms who won’t be able to hear their loved ones’ voices.”

In Wayland, Eleanor Lagasse said her grandson, Robert, 29, a civilian groundskeeper on the base, is OK.