The 18-year-old Quast later died from the wound.
"I don't know if I'll ever forgive you for what you did," Rashell Quast, the slain girl's mother, said Wednesday as Neri stood for sentencing in 3rd District Court. "You might as well have been the one who put the knife in her."
After a jury this year convicted Alzaga, 22, of murder and a judge sentenced him to up to life in prison, Neri took a plea deal. The 21-year-old Neri pleaded guilty to aggravated robbery, a first-degree felony. In exchange for some cooperation with officials, a charge of murder was reduced to second-degree felony manslaughter.
Prosecutor Peter Leavitt said Neri was initially hesitant to assist police and prosecutors because he knew Alzaga was dangerous. For that same reason, Leavitt said, Neri should have known he was putting Quast's life at risk when he set up the drug deal.
"He put her in the crosshairs of this person he knew was very, very dangerous," the prosecutor said. Leavitt said Quast was on a troubled path and her drug dealing caused her parents great concern. "But it wasn't a fatal path. Heather Quast met her untimely death because she crossed paths with Christian Alzaga and those paths intersected at Jose Neri."
Defense attorney Paul Quinlan said Neri had only known Alzaga for about a week before plotting the robbery and did not know the man was dangerous. Quinlan said his client had struggled with drugs, but only had minor assault charges on his juvenile record. The attorney asked Judge Terry Christiansen to run the sentences concurrently so Neri could potentially be released from prison sooner.
Neri, dressed in a yellow Salt Lake County jail jumpsuit, read a letter of apology to Quast's family.
"I made a mistake that I will not be able to change," he said. The man added, "I feel remorseful for my actions and will make the best of my time in prison."
Christiansen sentenced Neri to five years to life in prison on the robbery charge and one to 15 years in prison on the manslaughter. He ordered the sentences to run one after the other.
"You set this in motion," Christiansen told the man.
On May 26, the second anniversary of the slaying, the Quasts placed flowers on the woman's grave and at the spot just off the parkway where she collapsed. There, they shared a moment of silence.
Outside the courtroom, Jerry Quast said he hopes police will able to catch a third man officials say was involved in his daughter's slaying. Cristian Garcia, 22, has been charged with murder in the deadly robbery but has never been arrested.
Still, Jerry Quast said Wednesday's sentencing brought some closure to his family. Over the years, the court proceedings have become easier, he said, but never easy.
"Heather is still gone," the father told reporters.