MARTINEZ -- A Benicia man charged alongside his son with the methamphetamine-fueled torture-murder of an 18-year-old Martinez man in 2009 will testify against his son in exchange for the promise of a 16-year prison sentence, a prosecutor told jurors Wednesday.

In his opening statement at the trial of 21-year-old Timothy "Timmy" Delosreyes III, Contra Costa County deputy district attorney Jason Peck said that the defendant's father will take the witness stand for the prosecution in hopes of securing a plea deal for his own role in the slaying of his son's childhood friend, Eric Bean. The deal hinges on the condition that the father, 38-year-old Timothy Delosreyes Jr., testify truthfully in the eyes of the Contra Costa DA's Office.

"He's in a very difficult position ... he may minimize his son's role, we'll see," Peck told the jury.

If all goes as planned, Timmy Delosreyes' trial will be the last in the case surrounding Bean, whose badly beaten body was discovered dumped on the side of rural McEwen Road in unincorporated Martinez on Dec. 21, 2009. Peck said the youth was killed the day prior by a foursome afraid of being implicated if Bean followed through with a desire to confess to breaking into his father's gun safe and stealing firearms.

Benicia resident Robert Gardner, 35, was convicted by jury in March of first-degree murder, torture and grand theft for his role in Bean's death, and is now serving a 29-years-to-life state prison sentence.

Gardner's wife, 32-year-old Melody Rives, has an agreement with the DA's Office that if she testifies truthfully against the men charged in the case, her murder charges will be dismissed and she'll be allowed to plead guilty to being an accessory, her attorney, Dirk Manoukian, said.

Bean and Timmy Delosreyes were friends as children and reconnected when Bean became involved in the Martinez and Benicia drug scenes a few weeks before his death, Peck said.

The day before he was discovered dead, Bean was kept captive for hours in a bedroom of the Delosreyes' home on Carolina Street in Benicia. He was hogtied, silenced with duct tape, and repeatedly beaten. The cause of death was blunt force head trauma and asphyxiation by strangulation.

There was testimony at Gardner's trial that Timmy Delosreyes was the lead perpetrator of the violence, and that at one point, he put a knife in Bean's mouth and then stepped on his head.

Peck told jurors that Timmy Delosreyes stated he had a limited role in the killing after detectives showed him video of his dad and Gardner implicating him.

"I'm too young to go down for this, I'm too young," Peck quoted an 18-year-old Timmy Delosreyes telling detectives during his arrest in early 2010.

Defense attorney G. Wright Morton indicated that Timmy Delosreyes' role in Bean's death has been exaggerated by his former co-defendants and asked jurors to keep an open mind while they hear the evidence.

He said the defendant's father was "hammering, yelling" directions at his drugged son during the incident and that Timmy Delosreyes whispered to Bean, "Eric, be quiet. They are going to hurt you."

Testimony continues Thursday in Judge Brian Haynes' Martinez courtroom.

Contact Malaika Fraley at 925-234-1684. Follow her at Twitter.com/malaikafraley.