AUSTIN, Texas (AP) — Prosecutors are dropping criminal charges against two juveniles after police identified a different gunman in a mass shooting in downtown Austin that killed a tourist and wounded more than a dozen others, authorities said Tuesday.

Authorities have said the June 12 shooting on Austin's 6th Street arose after an argument between two groups of teenagers from the nearby city of Killeen. Douglas John Kantor, 25, was killed by gunfire.

Police initially arrested 17-year-old Jeremiah Tabb on an aggravated assault charge and another juvenile, whose name wasn't released. Tabb was charged as an adult.

Austin Interim Police Chief Joseph Chacon said Tuesday that investigators identified a different person, 19-year-old De'ondre White, as the shooter and a warrant for murder has been issued for his arrest.

White is not yet in custody, Chacon said.

Chacon said Tabb and the arrested juvenile were both involved in the dispute and had guns, but ballistics evidence determined that the shot that killed Kantor came from White's gun.

"These two individuals were involved. This is not people who were innocent bystanders or somehow incorrectly identified in this case," he said. 

Travis County District Attorney Jose Garza said his office chose to dismiss the charges against Tabb and the juvenile because they wanted to focus on the murder case. 

"When the time comes we will evaluate the totality of the evidence in this case. If the evidence bears it out, both people will be appropriately charged," Garza said.

Tabb was still jailed in Travis County on Tuesday morning and it wasn't clear whether he had an attorney who could speak on his behalf.