A former auto mechanic should be executed because he killed Carlie Brucia in order to cover up evidence that he had kidnapped and raped the 11-year-old girl, a prosecutor said Monday.

Joseph Smith's desire to avoid arrest for the abduction and sexual battery of the girl was one of six "aggravators" that justify a recommendation of death, prosecutor Debra Riva told jurors on the first day of the sentencing phase of Smith's trial.

Smith wanted "to eliminate Carlie as a witness," Riva said. "The defendant did not have to kill the girl."

Other aggravating circumstances, Riva said, include that the victim was under 12, Smith was on probation for possession of cocaine at the time of the murder, and the slaying was premeditated and "heinous, atrocious and cruel."

Defense attorney Carolyn DaSilva asked jurors to recommend sparing Smith's life. She noted that he had battled back pain, depression and drug addiction for the past dozen years and said relatives, friends and a drug-addiction expert would testify how "a man with good qualities could have fallen so far."

"You will hear from witnesses who can tell you about Joe's good qualities ... even though he was unable to control his drug addiction," DaSilva said. "You will hear from people who care about Joseph Smith, and that his life has value."

Her slaying received worldwide attention because her abduction on Feb. 1, 2004, was captured by a car wash surveillance camera. Her body was found five days later outside a church.

Circuit Judge Andrew Owens, who ultimately will decide the sentence, said he would give the jurors' recommendation "great weight." Over the objections of the defense, the judge also said he would allow jurors to listen to victim impact statements from Carlie's father, mother, stepfather and a teacher.

The same jury convicted Smith on Nov. 17 of kidnapping, sexual battery and first-degree murder. Carlie's murder spurred the introduction of federal and state legislation to crack down on probation violators.

Jurors must consider aggravating circumstances that would justify a recommendation of death by lethal injection and mitigating circumstances that would persuade jurors to recommend life in prison without parole. Their vote does not have to be unanimous.