THE COLONY (CBS11) – Police believe he shot and killed his own brother over a cell phone.

John Davis, 38, is now being charged with murder for the shooting death of Chandler Davis.

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John Davis

Chandler Davis became well known shortly after the deadly police ambush in Dallas on July 7, 2016.

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(credit: CBS 11 News)

As a retired U.S. Army combat medic, he stood at attention in full uniform at Dallas Police headquarters to honor the fallen and show the public the true conduct of a veteran.

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(credit: CBS 11 News)

“That’s the way, the kind of guy he is,” said Ashton Penington, a close friend. “He didn’t want to sit there and talk about it. He actually did it.”

Penington grew up with Chandler Davis. The news of his murder hit Penington hard.

“I lost a best friend and a brother and the world lost a good honest guy you don’t see now and days,” said Penington.

Police said a heated argument broke out between the Davis brothers. Chandler accused John of stealing a gun that belonged to him.

Investigators believe John Davis started recording their argument on his cell phone. Police said Chandler then took the phone and that is when they believe John Davis shot his little brother.

“They had a little tension, here and there. I know about all their little problems but I would have never guessed in a million years that it would have escalated to something like that,” said Penington.

Given Chandler Davis’ past public display of police support, Officer Kyle Koiner with The Colony Police Department said the case tugs on their hearts.

“It’s still hard to wrap our minds around that why somebody would do this over something so trivial and so small,” said Koiner.

Document show that when detectives asked John Davis why he feared for his life, “…the Defendant said that the victim was threatening to break his cell phone and destroy the evidence that was on it.”

Koiner said he did not believe the situation rose to the level of using deadly force.

John Davis is being held in jail on a $100,000 bond.