MIDLAND, Texas (Reuters) - All four men killed when a freight train collided with a parade float honoring wounded American war veterans had served in the U.S. Army, police said on Friday, as investigators descended on the West Texas oil town of Midland to search the wreckage.
At least 16 other people were injured during the parade on Thursday at the start of what was meant to be a weekend of events including a banquet and a hunting expedition to salute U.S. veterans of the Iraq and Afghanistan wars.
Midland police identified the dead as: Sergeant Major Gary Stouffer, 37; Sergeant Major Lawrence Boivin, 47; Sergeant Major William Lubbers, 43; and Sergeant Joshua Michael, 34.
In Washington, the Army said Lubbers was retired from the military but could not immediately confirm whether the others were retired or active duty at the time of the accident.
The National Transportation Safety Board (NTSB) sent 16 experts to the scene to examine evidence including video from a forward-facing recorder on the train, officials said.
One person remained in critical condition and four were stable on Friday at a Midland hospital, a spokesman said. Another person was in serious but stable condition at a Lubbock hospital. Ten more were treated and released, police said.
The tragedy occurred as two flatbed trailers carrying the veterans, some of whom suffered major injuries in combat in Iraq and Afghanistan, attempted to cross railroad tracks during the "Hunt for Heroes" parade.
"The first flatbed crossed the train tracks completely. The second did not make it across before being struck by the train," a police statement said.
Veterans and their spouses jumped off the trailers to escape the collision. There were 26 people on the float that was hit by the Union Pacific train including a dozen veterans, a dozen spouses and two escorts, officials said.
"It's hard to look at. It's a very tragic event, very unfortunate," Midland Police Chief Price Robinson said from the site of the accident on Thursday.
The train and trailer remained in place on Friday morning at the site of the crash.
The NTSB said it would not determine a probable cause of the accident or provide any analysis while its investigators were at the scene. It said it had not yet determined if the grade-crossing warning system was working at the time of the accident.
A Union Pacific Corp spokesman referred questions on the investigation to the NTSB.
A woman who was riding a float that crossed the tracks ahead of the one struck in the accident said on Friday she heard a train horn and then people started to leap from both trailers.
"As soon as we crossed the tracks, we heard the train," Pam Shoemaker said, adding that she saw a railroad crossing bar start to come down just before the crash.
Many of the veterans honored in the event had served multiple deployments in Iraq and Afghanistan, according to event organizers. Some were said to have been shot or wounded by bombs and suffered traumatic brain injuries or post-traumatic stress.
The Pentagon said in a statement that Defense Secretary Leon Panetta, who is traveling in Asia, "was deeply saddened by news of the tragic accident."
Dr. Sudip Bose, a veteran who had been a frontline physician in Iraq, said he volunteered to provide medical help and was summoned to the crash scene. He said he had to set aside his emotions to tend to the injured.
"It was chaotic at times, gruesome at times," said Bose, a doctor in Odessa, Texas, who said veterans were applying tourniquets and pressure to injuries.
Midland Mayor Wes Perry and pastors Patrick Payton and Roy Smith held a prayer vigil on Friday morning attended by more than 100 people at a park, including veterans and family.