BOISE, Idaho (KTVB) -- A Nampa man who was shot in the head Saturday evening has died, police confirmed Tuesday morning.

Kyle Jackson, 26, had been at Saint Alphonsus Regional Medical Center in Boise since the shooting.

Police say he was shot after an argument with the occupants in a black SUV. The altercation came after witnesses saw Jackson standing on a street corner, waving a red bandanna, yelling and making obscene gestures.

Kyle Jackson
Kyle Jackson (Photo: Nampa Police)
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An officer spoke with the man after witnesses called police, telling him he could be arrested for disturbing the peace if he did not stop, Nampa Police Sgt. Joe Ramirez said. The officer also warned Jackson that someone might take offense to what he was doing.

Hours later, someone did, police say.

Twenty-year-old Alberto Chavez was a passenger in a vehicle when he began to argue with Jackson, police say. The men are documented members of rival gangs.

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At some point during the argument, Jackson slashed Chavez in the face with a knife, before turning and walking away. Chavez shot the man in the back of head with a .38 revolver, police say.

“What a senseless tragedy,” Nampa Police Chief Craig Kingsbury said in a statement. “We just cannot tolerate this type of violence and behavior as residents of the City of Nampa. We are very fortunate to have had the help of concerned citizens who came forward and to all our law enforcement partners who helped with the arrest and capture of those responsible. Our thoughts and condolences go out to the Jackson family.”

Chavez was originally charged with with aggravated battery, destruction or concealment of evidence and aiding and abetting a felony eluding, and is held on $1 million bail. Ramirez said charges will likely be amended to murder or manslaughter now that Jackson has died from his injuries.

The charging decision will ultimately be up to the Canyon County Prosecutor's Office.