The gunman who killed 26 people at a small-town Texas church went aisle to aisle looking for victims and shot crying babies at point-blank range, a couple who survived the attack said.
Rosanne Solis and Joaquin Ramirez were sitting near the entrance to the First Baptist Church in Sutherland Springs on Sunday when they heard what sounded like firecrackers and realised someone was shooting at the tiny wood-framed building.
In an interview with San Antonio television station KSAT, Ms Solis said congregants began screaming and dropped to the floor. She could see bullets flying into the carpet and fellow worshippers falling down after getting hit.
For a moment, the attack seemed to stop, and worshippers thought police had arrived to confront the gunman - 26-year-old Devin Patrick Kelley - but then he entered the church and resumed "shooting hard" at helpless families, she added.
The gunman checked each aisle for more victims, including babies who cried out amid the noise and smoke, Mr Ramirez said.
The couple survived by huddling close to the ground and playing dead. Ms Solis was shot in the arm, and Mr Ramirez was hit by shrapnel.
Another 20 people were wounded.
Investigators collected at least 15 empty magazines that held 30 rounds each at the scene, suggesting Kelley fired at least 450 rounds.
Later it emerged that Kelley had been treated at a mental health centre in New Mexico and briefly escaped in 2012. He was also caught trying to bring guns onto Holloman Air Force Base in New Mexico when he was stationed there, according to an El Paso police report obtained by KPRC.
Kelley, who was 21 at the time, had made death threats against superior officers, the report said.
He was committed to a mental health facility in Santa Teresa, New Mexico, but at some point escaped and was later found by police at a bus station in downtown El Paso in June 2012.
The news emerged as investigators continued analysing the scene of the massacre and tried to gain access to the gunman's mobile phone, a longstanding challenge for the FBI in thousands of other cases.
Authorities aimed to conclude the crime-scene investigation by Wednesday evening. Investigators have no reason to believe anyone conspired with Kelley, who acted alone, said Texas Department of Public Safety Regional Director Freeman Martin.
Mr Martin repeated earlier statements that the shooting appeared to stem from a domestic dispute involving Kelley and his mother-in-law, who sometimes attended services at the church but was not present on Sunday.
"We don't know what he was thinking or what was in his mind," Mr Martin said. "There was conflict. He was upset with the mother in law."
The gunman's phone was flown to an FBI lab for analysis, but agents have yet to access it, said Christopher Combs, who is in charge of the agency's San Antonio division.
Kelley had a history of domestic violence that spanned years before the attack and was able buy weapons because the Air Force did not submit his criminal history from his time in the military to the FBI, as required by military rules.
If Kelley's past offences had been properly shared, they would have prevented him from buying a gun, the Air Force acknowledged on Monday.
At a news conference in South Korea, Us President Donald Trump was asked if he would support "extreme vetting" for gun purchases in the same way he has called for "extreme vetting" for people entering the country.
He responded by saying stricter gun control measures might have led to more deaths in the shooting because a bystander who shot at the gunman would not have been armed.
"If he didn't have a gun, instead of having 26 dead, you would have had hundreds more dead," Mr Trump said.
Brooke Army Medical Centre in San Antonio said it was treating seven victims of the shooting - five adults and two children.
Spokeswoman Elaine Sanchez said their conditions ranged from fair to critical.
Officials with University Health System in San Antonio said they are treating four patients - two adults and two children.
Spokesman Don Finley said their conditions ranged from serious to critical.
Megan Posey, with Connally Memorial Medical Center in Floresville, about 10 miles from Sutherland Springs, reported one patient was in a stable condition.
Authorities said Kelley shot himself following a chase by two local residents.
Officials said that the tally of those killed in the shooting included an unborn child.
Crystal Holcombe was eight months pregnant when she and three of her children were killed at the service. Her husband, John, was injured in the shooting.
Authorities had previously said the age of the victims ranged from 18 months to 77 years.
The inclusion of the unborn child means nine of the 26 victims killed were members of the Holcombe family.
Doctors at Connally Memorial Medical Centre praised the victims of the shooting for being calm and brave.
Dr Kenneth Kingdon said the patients were "a little scared" but calm.
"They were all very cooperative and amazingly brave, considering the situation they'd been in."
D Kingdon said that in general, the victims had multiple gunshot wounds.
Wilson County Sheriff Joe Tackitt said the pastor of the church said the gunman attended their Fall Festival on Halloween night and his behaviour did not raise any alarms.
Mr Tackitt told reporters: "The pastor told me he was here at the festival Halloween night, saw him in the crowd."
He said the pastor told him Kelley had attended services at the church before.