The gunman who killed a U,S.

soldier in a gunfight with police in Baton Rouge, Louisiana, Tuesday night was identified by authorities as an Army veteran who served in Afghanistan and Vietnam.

He had been living in a state of disarray for some time.

Police identified the suspect as 37-year-old Dillon Lee Simmons, who has been charged with murder, a felony, and attempted murder.

A police source told the Associated Press that Simmons has no prior record and was the last known person to live in the home where he killed the veteran.

Louisiana Governor John Bel Edwards said Simmons was killed “under circumstances that were untenable.”

“I am sickened by the senseless act of violence and heartbroken by the loss of life,” Edwards said in a statement.

“The Louisiana state Police are investigating this incident as a domestic-related shooting.”

Simmons lived at the home in the early morning hours of Tuesday.

Police said they did not know whether Simmons was armed at the time.

Louisiana State Police spokeswoman Tanya Lewis said police received a 911 call about the shooting at 11:15 p.m. local time.

Simmons was shot in the chest and the head, Lewis said.

Authorities identified the deceased as Lance Corporal Joseph Bales, 30, of Monroe, Louisiana.

Bales was a member of the 1st Battalion, 29th Infantry Regiment, 1st Cavalry Division, Fort Hood, Texas, Lewis told CNN affiliate WGNO.

“He was the best guy you could ever ask for in any situation,” Bales’ wife, Kimberly, told CNN.

Simmons lived with his wife, a U-Haul truck driver, and had three children, according to his Facebook page.

The family has been in crisis since the shooting, according in a letter from the family that Simmons posted on social media, which was shared by the Associated News.

“You are not alone,” it said.

“Your family is our family.”

The family is still in mourning.

“I just want you to know that I’m not going to let you down,” the letter read.

“My love to my family, my best friends, my family.

You are my people.

I want you all to know we love you, we love each other and I love you even more.”

The Associated Press contributed to this report.