On Aug. 31, 2013, Gonzales was at a house near 900 South and 300 West celebrating his sister's birthday.
Jessica Martinez, who took the stand in Wednesday's preliminary hearing, said the party stretched on through the night. Most people there were drinking. Some did drugs. Later, a fight broke out between her brother and the defendant's brother, Nicholas Valdez.
"I'm not exactly sure how it started; I just remember looking over and they were already fighting," Martinez said. "After the shooting, I just remember everyone running and my brother laying there."
Witnesses have told police that Donald and Nicholas Valdez were at the party flashing hand signs associated with the gang Varrio Loco Town. Eventually Nicholas Valdez got into a fist fight with Gonzales, who was a member the 21st Street gang, a VLT rival.
The fight moved outside at about 6:55 a.m., where Nicholas Valdez allegedly pulled out a silver handgun and fired two rounds. A fragment struck one of the bystanders at the party, according to court documents.
Video surveillance from a restaurant nearby allegedly showed Nicholas Valdez firing the handgun into the air and into the sidewalk. Originally, Nicholas Valdez was arrested on suspicion of Gonzales' murder, but investigators later found evidence that tied Donald Valdez to the crime.
The only witness to the shooting, Tiara Bennett, said the night felt like a "blur" and she didn't remember many details surrounding the alleged crime.
She wasn't sure she saw the gun, just heard shots. She couldn't remember what the assailant was wearing.
But when Gonzales was shot, Bennett testified, she was sure the shooter shouted, "Don't ever [mess] with my homeboy."
Donald Valdez was found running near the parking lot of a nearby Target store with dried blood on his hand and sweat streaming down his face, officials have said.
Gonzales was found dead from a gunshot to his head. A black rosary necklace lay shattered nearby an item witnesses said Donald Valdez was wearing all night.
But Salt Lake City Police Detective Thomas Flores said it was the gun casings that led police to believe Donald made the fatal shot.
The shell casings next to Gonzales' body matched those from a Glock pistol, which was hidden along with some of Donald Valdez's clothes in a nearby alley.
The defendant will next appear before 3rd District Judge Vernice Trease on June 13, at which point he will enter his plea to the charges against him.
Nicholas Valdez was charged with two felony counts of discharging a firearm one second-degree and the other third-degree and one third-degree felony count of obstructing justice.
According to court documents, Nicholas Valdez is expected to enter into a plea agreement with prosecutors by the end of the month.