SUTHERLAND SPRINGS, Texas - A gunman opened fire inside the First Baptist Church in Sutherland Springs on Sunday, killing 26 people and wounding 20 others, authorities said. Officials updated the public on the latest from the investigation during a news conference Monday.

Authorities say the Texas shooting suspect's mother-in-law received threatening texts from gunman. 

"There was a domestic situation going on within this family. The suspect's mother-in-law attended this church," an official said during the briefing update.

Texas Governor Greg Abbott called the attack the deadliest mass shooting in his state's history. Officials said 23 people were found dead inside the church, two outside, one died after being rushed to a hospital.

The shooting suspect has been identified as 26-year-old Devin Patrick Kelley, federal law enforcement sources told CBS News.

In the news conference, officials released the following updates:

  • Three firearms were recovered
  • The suspect did not have a license to carry
  • There are video recordings from inside the church, but officials are not ready to discuss them
  • The suspect called his father after the shooting
  • His mother-in-law attended the church, and officials say she had gotten threatening texts from Kelley

On Sunday night, authorities only identified the suspect as a young white male. They said he was seen dressed in all black and tactical gear -- including a "ballistic vest" -- at a local gas station at 11:20 a.m. He then exited his vehicle, crossed the street and began firing an AR-15 style weapon at the church, officials said. The suspect entered the church and continued to fire.

As he exited the church, a local resident grabbed his gun and pursued the suspect, who dropped his weapon and fled the scene.

The suspect was later found dead inside his vehicle. Officials are unsure if he was shot by a resident or suffered a self inflicted gunshot wound, said Freeman Martin, regional director of the Texas Department of Public Safety.

Kevin Jordan, a resident who lives near the church, told CBS affiliate KENS-TV he witnessed the deadly shooting and saw a resident pursue the gunman. "If it wasn't for him, the guy wouldn't have stopped," he said.

Jordan described the resident who confronted the suspect as someone who would do anything for anyone. He said he watched the resident shoot at the suspect while taking cover behind a vehicle.

Air Force spokesperson Ann Stefanek said in a statement that Kelley is a former U.S. Air Force member who served from 2010 to 2014. Records confirm Kelley previously served in logistics readiness in New Mexico until his discharge in 2014, Stefanek said.

Kelley was court-martialed in 2012 for two counts of assault on his spouse and assault on their child, Stefanek said. He received a bad conduct discharge and confinement for 12 months.

Officials have not released all the names of the 26 people killed, but said they ranged from 5 to 72 years old.

Annabelle Pomeroy, the 14-year-old daughter of the church's pastor, was one of the victim's killed in the shooting, her mother, Sherri Pomeroy, told CBS News via text message.

"My husband and I were ironically out of town in two different states. We lost our 14-year-old daughter today and many friends," Pomeroy said Sunday.

She added, "Neither of us have made it back into town yet to personally see the devastation. I am at the Charlotte airport trying to get home as soon as I can."

President Trump, who is on his first presidential trip to Asia, addressed the situation from Tokyo, calling it a "horrific shooting" and an "act of evil."

"Victims and their families were in their sacred place of worship. We cannot put into words the pain and grief we all feel," Mr. Trump said in televised remarks.

"In dark times such as these, Americans do we what do best and we pull together. We lock hands and we joins arms. Through the tears and through the sadness we stand strong."

Mr. Trump pledged his full support to the state of Texas and the local communities affected by Sunday's attack.

Late Sunday evening, around 100 people gathered near the church to remember the victims who were innocently gunned down earlier in the day.

Gov. Abbott attended the vigil and met with community members in the midst of the tragedy.

The Associated Press contributed to this report.