JACKSONVILLE, Fla. -

A 20-year-old man convicted of first-degree murder in the stabbing death of a 21-year-old Navy wife he met on Craigslist is sentenced to Florida's death row.

Judge Elizabeth Senterfitt formally sentenced David Sparre to death for killing Tiara Pool by stabbing her 89 times. She told Sparre that he forfeited his right to live at all.

Sparre didn't show any visible emotion when Senterfitt called him to the bench and announced her decision. The judge's words to Sparre were that the scales of life versus death tilted "unquestionably toward the side of death."

As soon as she said that, there were a lot of tears in the courtroom and a lot of emotion, especially from Sparre's family.

Pool's family said they're relieved by the death sentence and that it means a lot to them and will mean a lot to Pool's two young sons.

"I just pray the boys will be able to make it through and they understand who their mother was and what happened to their mother," said Valarie Speed, Pool's aunt. "I'm just overwhelmed right now. I can't even do this. I'm just so excited."

During the sentencing, the judge read a letter Sparre wrote from jail to an ex-girlfriend in which he told her he killed Pool for the thrill of it and that he would do it again. [Read full story]

"I planned on doing what I did. You want the truth? I did it for the rush," Senterfitt said as she read the letter Sparre wrote. "I planned for a week and a half how I would do it. I'm not even going to lie -- I enjoyed it and I hope to do it again."

"I'm just too happy it's all over with," Speed said. "This has been so long for our family. We're happy that he wrote the letter. That gives us some kind of closure. I'm just so happy this is all over with. He got what he deserved."

"To me, I am convinced that I sat across the table from evil. It really is," prosecutor Bernie de la Rionda said after the sentencing. "You see him close up, you can see evil in his face."

Defense attorneys say they're not only disappointed with the judge's decision, but they're also disappointed Sparre went against their advice and didn't allow them to present any evidence or witness testimony during the penalty phase -- a move they said could've changed the outcome.

They said they also have doubts about that letter.

"The difficulty of this letter is that we've got a lot of questions about this letter, why it was written, how it was written, things to that nature, and we believe there may be more to the purpose of writing that letter than what was brought out," defense attorney Michael Bateh said.

Before the jury unanimously recommend the death penalty in December, Sparre went against the advice of his attorneys and waived his right for witnesses to testify on his behalf during the sentencing.

Because of Sparre's request that his defense team called no witnesses during the penalty phase of the trial, the jury only heard from three prosecution witnesses delivering victim impact statements.

The judge said that by the defense not being able to bring up witnesses, Sparre eliminated more than 25 mitigating factors in his defense, ranging from his family's troubles, such as abuse, to medical factors, such as suffering from post-traumatic stress disorder and attention deficit disorder.

"What's going through my mind is, a flower has been plucked from our garden. That flower will never be there anymore, but I thank God that justice has taken place," Hattie Roche, Pool's grandmother, said after the jury recommended the death penalty. "It aches because we don't know why this happened. But the only thing we can do is rally around those two little boys and be all that we can be to them, and know that Tiara is looking down on us."

During the trial, prosecutors described what they called the ruthless and violent killing of Pool in her Hodges Boulevard apartment in July 2010.

"Eighty-nine. Over 89 stab wounds or cuts made by that man when he brutally killed the young lady," de la Rionda said during the trial. "What killed this innocent young lady was major stab wounds to her back. She was cut across her neck, she was stabbed across her back numerous times, and she was left on her bedroom floor naked, left to die."

Prosecutors said Pool posted an ad on Craigslist seeking friendship. They said Pool's husband was out at sea, and they were having problems in their marriage. Prosecutors said Pool's sons were out of town with her in-laws when she was killed.

Attorneys said Sparre, who was living in Georgia, responded to the online ad, and he and Pool text messaged each other for about a week until they finally met in Jacksonville.

Sparre told Pool he was visiting his grandmother, who had to go to St. Vincent's Medical Center, prosecutors said. Surveillance video shows him walking around the hospital.

Prosecutors said the two met at the hospital, but eventually went back to Pool's apartment.

Prosecutors said Sparre not only killed Pool with her own kitchen knife, but stole some of her things before leaving and heading back to the hospital. They said he even sold her PlayStation to a pawn shop in Georgia.

Police said it was four days until a concerned friend went to check on Pool and found her dead in her bedroom.