Graham

NEW BRAUNFELS, Texas (CNN) -- The jury resumed deliberations Friday at 9:15 a.m. (10:15 EDT) in the trial of former Air Force Academy cadet David Graham, who is accused of murdering a 16-year-old girl at the request of his girlfriend.

After closing arguments on Thursday, the seven men and five women began deliberating and broke after nearly six hours without reaching a verdict. State District Judge Don Leonard did not sequester them.

Graham, 20, faces up to life in prison if convicted of murdering Adrianne Jones in December 1995 near Fort Worth, Texas, on orders from his jealous girlfriend, Diane Zamora, after he confessed to a tryst with Jones.

Hartmann

As several onlookers in the packed courtroom sobbed, prosecutor Michele Hartmann told the jury that Jones was an innocent victim of an obsessive love affair between Graham and Zamora.

"She (Jones) was sacrificed on the altar of David Graham's ego, his cowardice, his utter lack of humanity," Hartmann said.

Fellow prosecutor Mike Parrish said a lengthy confession typed out by Graham for police proved that he killed the girl by bludgeoning her and shooting her twice in the head while Zamora looked on, shouting "shoot her, kill her, shoot her."

But defense attorney Dan Cogdell argued that an angry Zamora, acting alone, killed Jones and accused prosecutors of trying to "sell" the jury several different theories on how the murder took place, none of them true.

"It's Wal-Mart prosecution ... 'We'll see if they buy this,'" Cogdell said. "They're walking you down the Wal-Mart aisle and trying to sell you something else."

Zamora

Zamora, 20, was convicted in February for her part in the crime and sentenced to life in prison. She was brought to the courtroom from jail Wednesday on a subpoena by the defense but refused to testify because her case is under appeal.

Cogdell also attacked the way police investigated the case, referring to them as "a confederacy of dunces," and said Graham's confession was a falsehood that, under intense pressure from police, he dreamed up to protect Zamora.

"It sounds like a Danielle Steel novel -- it's full of prose, it's full of pretty language, it's full of heart-tugging memories," Cogdell said. Steel is a popular romance novelist.

During its deliberations, the jury asked to see several pieces of evidence, including a copy of the confession and a section of Texas law regarding whether confessions illegally obtained by police can be used against the defendant.

Cogdell said in opening arguments that Graham was not even present at the murder scene. He shocked the courtroom Wednesday when he rested his case without calling a single witness.

In the confession, Graham said Zamora became furious when he told her he had sex with Jones, a teammate on the high school track team. He said Zamora demanded that he kill Jones to prove his love.

They allegedly lured her into their car in the early morning hours of Dec. 4, 1995, and drove her to a remote area outside of Fort Worth where she was hit on the head with a dumbbell, then shot twice in the head by Graham with a 9mm Makarov pistol.

As they drove away, he wrote that "the first things out of our mouths were 'I love you."'

The two were high school seniors at the time of the murder, but got appointments to the service academies in 1996.

The crime went unsolved for nine months until Zamora confessed to her Naval Academy roommate, who went to police. The pair was arrested in September 1996.

The jury has three possible charges on which it can convict Graham -- capital murder, murder, and aggravated kidnapping.

Prosecutors said the jury should convict Graham of capital murder, which would bring an automatic sentence of life in prison with no chance of parole for 40 years. Jones' parents asked that prosecutors not seek the death penalty.

Murder and aggravated kidnapping carry a range of punishment from five years probation to life in prison, to be determined by the jury.

The trial was moved to New Braunfels in central Texas because of intense publicity in Fort Worth, 200 miles north.

Reuters contributed to this report.

"The Cadet Murder Case" by A. W. Gray "Blind Love: The True Story of the Texas Cadet Murders, Vol. 1" by Peter Meyer "Double Jeopardy: Obsession, Murder & Justice Denied" by Bob Hill "O. J. Unmasked: The Trial, the Truth, & the Media" by M. L. Rantala "Power to Harm: Mind, Medicine, and Murder on Trial" by John Cornwell Click here for additional reading on Murder Trial