HEBER — Prosecutors filed a charge of aggravated murder Wednesday against a second man they say is responsible for the death of Ashley Sparks, the 21-year-old found shot in the back near Jordanelle State Park in December.

Prosecutors say Joshua Binkerd, 22, was the gang leader of the small group that felt threatened by Sparks and her threats to go to police with incriminating information about some kind of criminal activity.

So Binkerd allegedly instructed fellow gang member Christopher Alvey, then 19, to deal with Sparks.

On previous occasions, Alvey had simply driven Sparks somewhere and abandoned her as a "strong warning" to not talk with police, Alvey's defense attorney Sidney Unrau said at Alvey's sentencing in June.

But on Dec. 26, as Alvey was traveling through the canyon, one of Binkerd's many calls finally made it through, in which "(Binkerd) made it clear to my client that he was to leave her and not bring her back," Unrau said.

Alvey had also understood that there was a "green light" out on Sparks, "which meant her life meant nothing to the people who gave out the green light," Unrau said.

So when Sparks got out of the van, Alvey shot her several times in the back then drove away.

Alvey pleaded guilty to aggravated murder and was sentenced to 20 years to life in prison with the possibility of parole.

Wasatch County Attorney Thomas Low said he wanted to secure a conviction against Alvey before filing charges against Binkerd. He's relying on the same facts, but with some additions and variations, as Binkerd wasn't the one who actually pulled the trigger. However, Low said Binkerd's involvement is still significant.

"The state's case is … (that) he's the one that put the events in motion that resulted in Ms. Sparks' death," Low said.

As part of Alvey's plea deal, Alvey agreed to testify against Binkerd, Low said.

"He's a witness," Low said. "I don't want to say the case would rise or fall based on him, but he's certainly an important witness."

The charge against Binkerd includes a dangerous weapon enhancement and an alternative charge of murder, Low said. This case is not a death penalty case — which is a possibility with a charge of aggravated murder.

Binkerd is currently serving a prison commitment for zero-to-five years on charges of forgery, theft, theft by deception and probation violations from older cases.

A first appearance date in 4th District Court has not yet been set.

At Alvey's sentencing, family and friends begged the judge for the possibility of life with parole, emphasizing Alvey's kind, sensitive nature, but his weakness for following others — good or bad.

"Until 2008, Chris had not been in trouble with the law," family friend Rebecca Stouffer said. "At that time, he met the wrong group of so-called friends. These friends saw his weaknesses, filled him with drugs, expensive gifts and false hope. It's difficult to envision the possibilities Chris' life could have taken had he not hooked up with this group of friends."

E-mail: sisraelsen@desnews.com