CENTENNIAL, Colo. -- The jury in the Sir Mario Owens trial decided Monday afternoon that he should be sentenced to death for gunning down a young couple, including a witness in a murder trial.

The Arapahoe County jury unanimously agreed that the death penalty was the most appropriate punishment for the murders of Javad Marshall Fields and his fiancee, Vivianne Wolfe.

Marshall-Fields' mother, who has been in the courtroom every day through the murder trial and now, through the penalty phase, cried quietly as the verdict was read. Wolfe's mother, Christina, dabbed her eyes with tissue.

"It's not a celebration but it does give me confidence in our justice system. I think if any case warrants the death penalty, it's this case," said Rhonda Fields.

It was three years ago this week that their children -- college sweethearts who had just graduated from Colorado State University -- died in a hail of gunfire as they were driving through an Aurora intersection. The ambush occurred in broad daylight -- just days before Marshall Fields was scheduled to testify in a murder case against Owens.

Dressed in a prison jumpsuit, Owens' looked straight ahead and did not show much emotion as the verdict was quickly read in a very quiet courtroom. His mother and father had similar responses.

"It's a very somber day. This is not something that we celebrate or take great joy in. We believe that it is a very just verdict. It's one that the fact and the evidence required under the circumstances but nobody takes any joy in such a verdict. There is a satisfaction, I think, for the families and the district attorney's office. I want to commend the jury for doing an absolutely phenomenal performance of their duties," said Prosecutor John Howard.

"Sentencing someone to death is something you don't do lightly," said a juror leaving the courthouse.

"It took hard work and dedication by everyone involved to come to grips with what was the right thing, the just thing to do," said the juror, who wished only to be identified as a 58- year-old government employee.

Another juror said the decision came after carefully reviewing all evidence and testimony.

"I don't think there was one thing that overshadowed everything else. I think having to come to this decision was so critical we had to look at everything," said the juror, 41.

Owens will be only the second person in the state to be on Colorado's death row. Currently, the only person on death row is Nathan Dunlap. He was convicted of killing four people at a Chuck E Cheese restaurant in Aurora in 1996.

Owens' mother later said that she disagreed with the sentence because only God should have the power to sentence someone to death.

"Today, the friends and families of Javad Marshall-Fields and Vivian Wolfe finally saw justice served on the man who brutally murdered their loved ones. These two victims did nothing to deserve their fate; they were simply trying to do the right thing. Instead, they were gunned down by a man who felt he had nothing to lose," Attorney General John Suthers said in a release. "The case of Sir Mario Owens demonstrates exactly why the death penalty remains a vital part of our criminal justice system ... Without the threat of a death sentence, a killer facing life in prison has virtually no disincentive to hunt down and kill those who would testify against him. It remains among the state's highest priorities to protect those who are brave enough to stand and testify against the unlawful. Sir Mario Owens rightly will be put to death for taking the lives of two very brave individuals."

The same group of six men and six women found Owens guilty of first-degree murder last month in the June 2005 deaths of Marshall-Fields and Wolfe. They began deliberating the death penalty on Friday, after a month of testimony, and came to their decision after eight hours.

The panel had to agree unanimously for Owens to be executed or he would have automatically be sentenced to life in prison.

Marshall-Fields had been scheduled to testify against Owens in a trial involving Fourth of July shooting at an Aurora park. During that shooting, Marshall-Fields' best friend, Gregory Vann, was killed.

Despite death threats and a "bounty" placed on his head, Marshall-Fields agreed to move forward and testify against Owens. He told his family he was scared for his life, but told detectives that had positions been reversed, Vann would have done exactly the same for him.

Even without Marshall-Fields' testimony, Owens was found guilty of that murder and was sentenced to life in prison.

Prosecutors had referred to Marshall-Fields as a "citizen witness" and said his execution was a brazen act against the justice system. Prosecutors said after Marshall-Fields was killed, already reluctant witnesses refused to cooperate with prosecutors or demanded special protection.

In fact, nine witnesses in the state have already been relocated out of state -- many of them moving their families with them.

The case has drawn so much scrutiny that a second layer of security was needed for the courtroom -- with guards checking security at the entrance to the court building, and additional guards posted outside the court room.

The judge also ruled that when Owens walks into the courtroom to hear the verdict, he had to be wearing his jail uniform instead of his street clothes -- which he wore during the trial. The sheriff's department argued that it was just too dangerous to have a suspect wear street clothing.

Owens becomes the third person on death row, joining Edward Montour Jr., 39, convicted of murder in the death of a guard at the Limon prison in October 2002, and Nathan Dunlap, now 33, who was convicted in the 1996 slaying of four people at a Chuck E Cheese restaurant in Aurora. A fifth shooting victim survived.

The last execution in Colorado was in 1997, when Gary Lee Davis, 53, was put to death by lethal injection for his conviction in the 1986 slaying of a Byers, Colo., woman.

Davis was the first person executed in the state since 1967, when the U.S. Supreme Court subsequently declared the death penalty unconstitutional. Luis Monge was executed in the Colorado gas chamber in 1967 for murdering his wife and three children. Prior to his death, Colorado averaged one execution per year, since the gas chamber replaced hanging in the state in 1934.

Monge was the last person put to death in the United States prior to 1977, when the death penalty was reinstated.