(CNN) -- A shooter killed 26 people at a Texas church and at least eight of those victims were members of the same family, according to a relative and a community leader who both spoke to CNN.
The mass shooting, which happened during a Sunday morning service, shocked the small town of Sutherland Springs, located about 30 miles east of San Antonio.
About 20 other people were wounded at the First Baptist Church. The massacre was called "the largest mass shooting in our state's history," by Texas Gov. Greg Abbott.
-- Using a rifle, the gunman shot victims between the ages of 5 to 72 years old, said Freeman Martin, a regional director with the Texas Department of Public Safety.
-- At least eight of the people killed were members of one family, according to a relative and a community leader. A woman who was about five months pregnant and three of her children were killed. The pregnant woman's brother-in-law and his young child were also killed, according to the community leader. Three other members of the same family were injured. CNN is not naming the victims at this time, as it isn't yet confirmed that their next-of-kin have been notified.
-- Among those killed included the 14-year-old daughter of the church's pastor, according to Sherri Pomeroy, the girl's mother. Her parents were traveling out of state when the shooting occurred.
--The shooter fled the church, was chased and later found dead in his vehicle, officials said.
-- A witness told CNN affiliate KSAT that he and an armed resident had pursued the gunman in a car chase.
-- Speaking from Japan, President Donald Trump expressed condolences for the victims during a Monday news conference and said he believes the shooting was caused by a "mental health problem," not an issue with US gun laws.
Who is the shooter?
The suspected shooter has been identified as Devin Patrick Kelley, 26, according to two law enforcement sources who have been briefed on the investigation.
Police have not officially identified Kelley as the shooter, but described the suspect as a white man in his 20s. Authorities have not said what may have motivated him.
Kelley was a member of the US Air Force and served at Holloman Air Force Base in New Mexico from 2010 until his discharge, according to Air Force spokeswoman Ann Stefanek.
Kelley was court-martialed in 2012 for assault on his spouse and assault on their child, according to Stefanek. Kelley served a year in confinement and received a bad conduct discharge. His rank was also reduced, she said.
In April 2016, Kelley purchased the Ruger AR-556 rifle he allegedly used in the shooting from a store in San Antonio, Texas, a law enforcement official said. There was no disqualifying information in the background check that was done when he was trying to buy the rifle, a law enforcement official told CNN.
How the attack unfolded
The shooter was first spotted at a Valero gas station, located across the street from the church at about 11:20 a.m. local time.
The suspect left the gas station, crossed the street and exited his vehicle, Martin said during Sunday's news conference.
He began firing before he entered the church, Martin said.
David Flores told CNN that his father saw the shooter.
"My dad saw the gunman run into the church building and then he heard shots and saw people running," Flores told CNN. "People covered in blood and screaming. It was pandemonium everywhere."
As the shooter left the church, a local resident used their own rifle to engage him, Martin said. The gunman dropped his weapon and then fled, while that citizen pursued him.
It turned into a brief chase into the neighboring Guadalupe County.
Johnnie Langendorff said he was driving to his girlfriend's house when he saw gunfire between the shooter and the armed resident.
The shooter was taking off in a Ford Explorer outside the church, Langendorff told CNN affiliate KSAT.
The resident who had a rifle "briefed me quickly on what had just happened and said we had to get him, and so that's what I did," Langendorff said.
They gave chase in his truck and called police. As they sped after him, Langendorff said the shooter "eventually lost control on his own and went off into the ditch."
"The gentleman that was with me got out and rested his rifle on my hood and kept it aimed at him [shooter], telling him to get out. There was no movement, there was none of that. I just know his brake lights were going on and off, so he might've been unconscious from the crash or something like that. I'm not sure."
Law enforcement later found the suspect dead of a gunshot wound inside his vehicle.
"At this time, we don't know if it was a self-inflicted gunshot wound or if he was shot by the local resident," Martin said.
A law enforcement official briefed on the investigation said multiple weapons were found in the shooter's car. The FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives are involved in the investigation.
Hours after the shooting, residents of Sutherland Springs hugged one another, held candles and sang hymns in a candlelight vigil Sunday night. Gov. Abbott attended the event, in which faith leaders offered words of solace and prayers.
Sutherland Springs is the kind of place where "everybody knows everybody," said Gloria Rodriguez Ximenez, who attended the vigil.
"This is a small, Christian town, a very small community," she said. "Everybody's united. Everybody's so close to everybody."
She knows the First Baptist Church's pastor and his family, including their daughter who died.
"I can feel the pain everybody's going through. There's so much hurt for a small town," Ximenez said.
Others echoed the feeling of shock and heartache.
"My heart is broken," Wilson County Commissioner Albert Gamez Jr. told CNN. "We never think where it can happen, and it does happen. It doesn't matter where you're at. In a small community, real quiet and everything, and look at this."
Twenty-three people died inside the church, which has a small sanctuary with wooden pews and red carpeting. Two died outside the church and one at the hospital.
"We don't know names of any of the victims at this time," said Wilson County Sheriff Joe Tackitt in a news conference Sunday evening. As victims are identified, next of kin will be notified, he said.
The wounded are being treated at three hospitals including the Connally Memorial Medical Center in Floresville, University Hospital and Brooke Army Medical Center in San Antonio.