A young soldier shot and wounded his wife outside a Dallas-area store and then gunned down a father of three who grabbed his own gun and tried to make a citizen's arrest, authorities say.

Arlington police say Anthony "T.J." Antell Jr., 35, saw Ricci Bradden shoot at the feet of his wife during an argument Monday outside of a Walgreens where she works, striking her once. She fled inside the store to call for help.

Antell retrieved a handgun from his vehicle and confronted Bradden in an attempt to make a citizen's arrest, but Bradden managed to slap it away and then fatally shot Antell, investigators say.

"What was really traumatic, the Good Samaritan's spouse was here and witnessed this," police Lt. Chris Cook told WFAA-TV. "I can't imagine going through that."

Bradden, a 22-year-old Army private, drove away and later turned himself in to authorities. At one point, he called his commanders at Fort Hood and confessed, according to an arrest warrant.

Bradden's wife, Quinisha Johnson, told WFAA on Tuesday that he came to the store because he was upset by a selfie she posted on social media that he thought made it seem she was seeking attention.

"And I was trying to explain it to him, that I married you. You're all the attention that I needed," she told the station. "And I could feel that he was getting mad, so I tried to walk off, and that's when I heard him pull the gun out."

The couple had only been married about two months.

Bradden was being held Tuesday at the Arlington jail on a murder charge. Online jail records didn't indicate if he had an attorney yet.

Cook said it's difficult to determine when an armed Samaritan should intervene in a deadly situation, The Dallas Morning News reported.

"Any time that you can be the best witness you can be, we always recommend that," he said. "Sometimes things turn out like this when you're trying to stop a bad guy."

Antell was a former Marine and fitness enthusiast who owned a CrossFit gym, according to the family's pastor, Marc Lowrance of Saint John the Apostle United Methodist Church in Arlington.

"He had a great sense of being a defender of what was right, we saw that with his family and with his business," Lowrance said. "He had a great ideal of protecting what was good and what was right."