(Court TV) — Already behind bars serving a 99-year sentence, Donald Keith Newbury may not have thought he had much to lose by escaping a Texas prison with six other inmates. But now Newbury is being tried for capital murder, after the escapees — who became known as the "Texas Seven" allegedly shot and killed a police officer during their six weeks on the lam.

While defense lawyers are likely to argue that it cannot be proven exactly which of the escapees shot and killed Irving, Texas, Police Officer Aubrey Hawkins, prosecutors say that Newbury is still guilty of capital murder for his role in the killing.

The issue will be one for a Dallas jury of seven men and five women to decide before Judge Vickers Cunningham as the case goes to trial Monday.

A Prison Break Leads to Murder

Following their Dec. 13, 2000, break from Connally Unit Prison in Karnes City, Texas, the group allegedly went on a stealing spree. On Christmas Eve, they were executing their third robbery together — this time of a sporting goods store in Irving, Texas.

But before the escapees could flee the scene, Officer Hawkins arrived. In a brief shoot-out, Hawkins was hit with 13 bullets — with six of them entering his head. He was then run over, authorities say, by the escapees' vehicle as they sped away.

The Texas Seven headed toward Colorado, where Newbury and Patrick Murphy, Jr., decided to splinter off from the group. After they parted and headed for Colorado Springs, the five that remained behind were captured. One of them killed himself before he could be taken into custody.

Shortly after the brown van Murphy and Newbury used to get to Colorado Springs was found by police, a hotel clerk tipped off authorities that the two were hiding out in a Holiday Inn.

On January 24, 2001, the pair entered into a six hour standoff with police. They surrendered peacefully, but not before airing their hostilities about the Texas prison system on television.

Murphy and Newbury each had five-minute call-in interviews with anchorman Eric Singer of KKTV, a CBS affiliate.

Singer would later say that of the two, Newbury was the angry one, the "James Dean, the rebel without a cause."

In his interview, Newbury pointed out that the escape was conducted as peacefully as possible, that the prison officers were hurt very little and only if they resisted.

"The system needs to be checked. It needs to be rebuilt, reconstructed. I'm not saying do away with it or nothing else. I'm just saying make something that will work," he said during the interview.

He noted that the Texas Seven could have made it a bloodbath and been out of there much faster, but instead moved slowly to do it "gently."

Newbury also claimed his latest sentence was unfair and out of proportion with lesser sentences people got for what he considered greater crimes. He said the system is designed to "make you fall" and talked about being told to quit his job when he was on parole "doing good."

"I don't see how the system is actually working," Newbury said. "It's fallen. I don't hold it against the administration or the officers involved in what we're doing."

"I've done crime, you know, you got to face the music," he said. "But there's got to be something within reason in the state of Texas. They're giving kids so much time that they will never get to see light again. Their life is gone. Now all they are is a roach in a cage. Things have to be changed, there has to be more rehabilitation in the system down there."

He talked about having to threaten to beat up one of his lawyers in order to get a new one because the attorney never came to see him.

Newbury also expressed that he was not afraid of dying, and as he was headed back to prison vowed to work for change.

"I'm stepping out of these doors with the sole purpose of honoring the person I love and to keep my voice in the media. I'm going to start writing...We're going to keep screaming. We're going to try to get something changed. Something's gotta change," he said.

Who is Donald Newbury?

A native of Albuquerque, New Mexico, Newbury attended school until the sixth-grade and later became an electrician, according to prison records.

The six-foot, one-inch, 200-pound inmate attempted to escape prison once before. In 1987, he and two fellow offenders allegedly overpowered two correctional officers in the Travis County Jail, but the attempt failed.

At the time the Texas Seven escaped, Newbury had the longest rap sheet of the group. A three-time felon, Newbury was convicted of armed robbery in 1981 and 1987. According to news reports, he was also suspected in about a dozen other robberies in the Austin area in 1986 and 1987, including three at a hotel, one of a cab driver, one of a Trailways bus and two in stores.

According to the Fort Worth Star-Telegram, after Newbury was released from his second stint in prison in the early 1990s, he reportedly moved in with a woman and her children. That woman later became his wife, Jacqueline Newbury. According to the Telegram, at that point in his life, Newbury had trouble getting work while on parole. He reportedly did some manual labor for a man who also had been in prison, but was forced to quit because it violated the parole rules against associating with ex-convicts.

On July 18, 1997, Newbury committed the robbery which landed him in prison for 99 years. That time he used a sawed-off shotgun to rob a woman at a La Quinta hotel in Austin. He allegedly took $65. The Telegram reports that Newbury was captured when authorities released a surveillance tape of the hold-up.

It was the conviction for that robbery for which Newbury was serving time at the time of the Texas Seven's escape. According to the Incident Review from the Texas Division of Criminal Justice, Newbury had no history of assault or violent behavior while incarcerated previously, with the exception of the attempted prison escape.

Newbury's former defense lawyer, Kent Anschutz, told the Telegram that Newbury is of average or above-average intelligence, and a "pretty likable old boy" who made some bad decisions.

The Capital Murder Charge

Prosecutors are expected to argue that when Hawkins arrived at the scene, the entire group surrounded the officer and began firing a continuous barrage of gunfire at him.

Though guns were later recovered, many were dissembled and it is unknown which convict used which pistol.

Jurors may conclude that Newbury did not shoot his gun, that he shot it but did not hit Hawkins or that he did hit Hawkins.

In any interpretation, however, prosecutors say he is still guilty of capital murder, either as a direct participant to the shooting or as a "party to the offense."

To prove Newbury was a party to the offense, prosecutors would have to show that he encouraged or acted with the intent of assisting or promoting the fatal shooting, or that the murder was committed during the course of a robbery committed by Newbury or his conspirators.

Defense lawyers have remained tight-lipped about their trial strategy.

The ringleader of the escapees, George Rivas — who was already tried, convicted and sentenced to death — testified during his trial that that nobody was supposed to die during the robbery. It is unclear whether or not he will testify at Newbury's trial.

If Newbury is convicted, jurors will be presented with three issues during the penalty phase. First, they must decide whether Newbury will be a continuing danger to society. Second, if they find that Newbury did not kill Hawkins, they must determine whether he intended for Hawkins to be killed or should have anticipated it. Finally, they must decide whether factors exist to mitigate against Newbury's receiving the death penalty.

Along with his fellow escapees, Newbury also faces separate charges in other Texas counties for escape, armed robbery and kidnapping in relation to the prison escape. Those charges, which are still pending, may or may not be pursued by prosecutors. Federal charges had also been brought against the escapees but were later dropped.