MIAMI — A jury decided Wednesday that a convicted sex offender should get the death penalty for the kidnapping, rape and murder of 9-year-old Jessica Lunsford, who was buried alive in trash bags just yards from her home.

The jury, on a 10-2 vote, brushed aside pleas for mercy and a life sentence from defense lawyers based on claims that John Evander Couey, 48, is mentally retarded and suffers from chronic mental illness. Jurors deliberated for about one hour.

The final decision on Couey’s fate will be made in several weeks by Circuit Judge Richard Howard, who is not bound by the jury’s recommendation but is required to give it “great weight.”

The Lunsford family showed no emotion when the decision was read, nor did Couey. Outside the courthouse, Jessica’s father, Mark Lunsford, thanked the jury with tears in his eyes.

“This is justice for Jessie, but not just Jessie,” Lunsford said. “I’m sure there are other victims out there. If you crossed paths with Couey and he hurt you, this is justice for you.”

Couey was convicted last week of taking Jessica in February 2005 from her bedroom to his trailer about 150 yards away, where he raped her. Despite an intensive search, the third-grader’s body wasn’t found until about three weeks after she disappeared — in a grave outside Couey’s home.

In closing statements, prosecutor Ric Ridgway called the crime “evil” and asked jurors to remember how Jessica died by suffocating in the hole Couey dug, accompanied inside the plastic bags only by a toy dolphin.

“She was in pain. In the dark. She was certainly terrified,” Ridgway said in his closing statement. “If this is not the person who deserves the death penalty, who does?”

Defense lawyers pleaded for mercy, arguing that Couey deserved no more than a life sentence in prison because of mental retardation and mental illness, neglect as a child and the effects of alcohol and drug abuse.

“No matter what you do, John Couey is going to die in prison,” said defense attorney Alan Fanter. “No child should have to die the way Jessica Lunsford did. But justice is not vengeance.”

Mentally retarded people cannot be executed under both Florida law and a 2002 U.S. Supreme Court decision. Ridgway scoffed at defense claims of extreme mental problems, noting that Couey carefully planned the crime and repeatedly lied to police in an attempt to escape blame.

“Does the defendant have mental problems? Probably,” Ridgway said. “They are not extreme. They do not control him.”

Juror Marvin Gunn, 38, said the panel considered the claims of mental problems.

“It’s not an excuse,” Gunn said. The biggest factor for him, he said, was “the fact that she was 9 years old.”

Earlier Wednesday, psychologist Harry McClaren testified that Couey is able to adapt to day-to-day life despite any mental challenges, including low IQ. Defense experts said Couey has an IQ of 64, below the standard retardation level of 70.

“In my opinion, he was able to function at a level higher than would be expected of a person with mental retardation,” McClaren said.

The trial was moved to Miami from central Florida because of heavy media coverage.

Jessica’s death led to tougher laws across the nation to keep better track of sex offenders and punish repeat offenders more severely.

Couey has a criminal record that includes 24 burglary arrests, carrying a concealed weapon and indecent exposure. He was designated a sex offender for exposing himself to a 5-year-old girl in 1991.