PHOENIX (CBS Local) — An Arizona man may have been shot and killed by another motorist for simply looking at him while stopped at a red light, police in Phoenix said.

Alex Mixon, 26, was driving westbound on Thunderbird Road near 30th Street on March 1, 2019, when his 2002 Dodge Dakota pickup truck suddenly crossed over into the eastbound lanes and left the roadway. Mixon’s vehicle clipped a power pole and went through a wall before coming to a complete stop.

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The incident was initially investigated as a single-vehicle crash.

“The Medical Examiner contacted us and said, ‘Hey, this man did not die of an accident or a collision. He died because of a gunshot wound,” said Sgt. Tommy Thompson of the Phoenix Police Department told CBS affiliate KPHO.

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After a lengthy investigation, homicide detectives arrested Nicolas Elliott, 30, on Thursday.

“They found he had been boasting about what he had done,” said Thompson.

Police say Elliot allegedly shot Mixon for merely looking at him while stopped at a red light. Investigators don’t believe the men ever argued or exchanged words.

Elliot faces charges of murder and aggravated assault.

“We now know why he was taken from us so unexpectedly, but it will take time to reconcile our hearts to it,” Mixon’s family said Friday in a statement.

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“Our family is thankful for all the hard work and dedication from the City of Phoenix Police. Without their efforts we would not have found out what happened to Alex and the person responsible for his death,” the statement read.