Sept. 24, 2009 -- In September 2008, more than five years after the gruesome killing of four youths in a Houston suburb, a lone defendant finally appeared in court, charged with capital murder.
The identity of the defendant shocked the families of the victims and the community at large. Christine Paolilla, 17 at the time of the murders, had been a high school classmate and close friend of two of the victims, Rachael Koloroutis and Tiffany Rowell, both 18.
On the afternoon of July 18, 2003, Paolilla and her boyfriend at the time, Chris Snider, drove to Tiffany's house in the manicured Clear Lake suburb to score drugs, she told police. Inside were Rachael, Tiffany, Tiffany's boyfriend, Marcus Precella, 19, and his cousin Adelbert Sanchez, 21.
Paolilla told police that at the house Snider got aggressive. He started arguing with Marcus, and shots were fired. When the assailants left, the four youths were dead.
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Click Here for Part 1 of the "Miss Irresistible" murder.
Acting on a tip, police arrested Paolilla three years later, in a San Antonio hotel room where she lived with a man she had meanwhile married, Justin Rott. Snider committed suicide after learning police were on his trail. Now Paolilla faced the murder charges alone.
Her family blamed the murders on Snider. "She was not capable of doing this," said Tom Dick, Paolilla's stepfather. "There's no doubt in my mind. ... What's happened is a tragedy. She's as much of a victim as these poor kids. She's not the one that did this. The one that did it is gone."
With what remained of a trust fund she'd received at 18, Paolilla hired Mike DeGuerin, a prominent criminal defense attorney in Houston.
"When the case was offered to me, I went and saw her in jail," DeGuerin recently told ABC News. "I saw a scared, frightened little girl, and I accepted the case."
Standing before the court, Paolilla pleaded not guilty.
For the first time the families of the victims come face-to-face with the accused killer.
"I couldn't take my eyes off her," said Ann Koloroutis, mother of Rachael. "I really hoped to see something in her eyes in the way of remorse. And it was unbelievable. You know, she never shed a tear unless it was for herself."
The crux of DeGuerin's defense was that the murders were committed not by Paolilla but by Snider.
"Christine Paolilla never intended for anybody to be hurt," he told the court. "And she didn't even know what Chris Snider was going to do."
After all, why would she want to kill her own friends?
"The person that did the killing was a warped psychopath," DeGuerin told ABC News. "When he came up dead, then they had nobody left except her to prosecute."
Rob Freyer, a former prosecutor for Harris County, Texas, dismissed that argument.
It's a bunch of crap. It's not true," Freyer told ABC News. "It's easy to blame somebody if they're dead. Who knows what he would've said if he were alive. But how convenient. It's what the Germans did at Nuremberg. Blame the dead. Blame the dead guy."
Freyer pushed the argument in court.
"She's going to tell you that she was so scared that he gave her a gun that she never used," he said. "She's guilty of murder. She's guilty of capital murder."
The prosecution's case seemed strong. During a police interrogation following her arrest, Paolilla had admitted to firing a pistol.
"I had made the gun go off," she told police.
Her interrogator asked her how many times she thought it went off in her hands.
"A million times," she said. "It felt like a million times."
'Two Guns Were Fired Simultaneously'
But Paolilla also had insisted that Snider forced her to take a gun.
"He's like come here, and then he shoved another gun and said 'just take this,'" she told police in a 2006 interrogation.
She added that Snider put his hand on top of hers, forcing her to fire.
"He was holding on to it, too," she told police. "... And I was scared and I was crying."
DeGuerin narrated his version of the scene for the jury.
"He put the .38 in her hands and she got it by the handle, and she's got her eyes closed," DeGuerin said. "He puts his hands over hers and he goes 1, 2, 3, bam, 1, 2, 3 bam."
Testimony about ballistics painted a different picture, however. Crime scene investigators pointed out that two victims, Tiffany and Adelbert, were found dead on the couch with their feet up, shot multiple times, with no sign of struggle.
Each was hit with bullets from two guns, the prosecution said, arguing that there were two shooters firing at the same time.
"It defies logic that this gun is emptied first and this gun is emptied second," said Craig Goodhart, a former prosecutor with the Houston District Attorney's office. "When you got multiple gunshots from both guns in the two kids on the couch who never move. ... These two guns were fired simultaneously."
There was also the question of why Paolilla didn't go to police after the murders. Paolilla had always said she didn't call the police because she was too afraid of Snider. But phone records show that she called him constantly after the crime.
"Over 1,100 calls are made from her to him and him to her," said Goodhart. "If you are so deathly afraid of someone, what are you doing on the phone with them? For over 1,000 phone calls!"
Finally the prosecution brought in their star witness: Paolilla's own husband, Justin Rott, who had joined her on an extended heroin binge in the months before her arrest. He said she had told him everything.
"She said before they walked into the house, Chris handed her a gun," Rott told the court.
A prosecutor asked, "Did she say, at this point, Chris forced it on her or ... threatened her?"
"No," said Rott.
The husband said Paolilla knew she was participating in a drug heist from the start, and when the bullets started flying, she didn't hesitate to join in.
"She said ... Chris shot first," Rott said. "[Then] she said they both started shooting."
In the most shocking moment of the trial, Rott described for the court what he said Paolilla told him about the final, cold-blooded minutes in the house.
"She told me that she told Chris that they had to go back," Rott testified. "She said she had to make sure they were all dead. ... She said when she went back in Rachael was there and she was still alive. She was choking on her own blood. She was gagging. She said that Rachael just kept asking, 'Why?'"
'Hitting Her and Hitting Her'
Then Rott described what happened next.
"She beat her to death. With the gun. She kept hitting her and hitting her and hitting her."
Family members of the victims were horrified and saddened listening to the testimony.
"You still don't know how she could be in the same room with Rachael, how she could see her smile, and still beat [her] in the back of her head," said Tiffany Koloroutis, Rachael's older sister. "I don't know how anyone could know her and do that."
George Koloroutis, Rachael's father, pointed out how young Paolilla was at the time.
"Hard to believe a 17-year-old girl would wreak such havoc and carnage," he said. "Very, very cruel, just a cruel murder. Savage."
The defense countered by calling Rott's trustworthiness into question. DeGuerin noted that Rott was a convicted felon and admitted drug addict. The lawyer said the husband ratted out his own wife to save his skin.
"He was facing a life charge for heroin," said DeGuerin. "So he sold his testimony."
Paolilla's family said Rott made a practice of seducing women in rehab and leeching off them as long as they had money. When her trust fund matured, Paolilla had plenty.
To drive home the point, DeGuerin called a string of women to the stand to relate similar stories of deceit and treachery. One said Rott had claimed he had the same kind of cancer as her father. Another said he would take her debit card and make unauthorized withdrawals.
"One thing that was established beyond any doubt whatsoever is that he was a lying scumbag," Judge Mark Kent Ellis told ABC News. "He picked up women in rehab and used them, abused them, took money from them."
Ann Koloroutis was disappointed that Paolilla, on the advice of her lawyers, declined to testify.
"I wanted to look her in the eye and have her say, 'I'm sorry,'" she said.
After nine days of testimony, lawyers began their closing arguments. Ultimately, the jury was left to decide: Was Paolilla a victim of circumstance, or a willing participant in the murders?
The defendant faced a mandatory life sentence if convicted.
"When you look at the charge you are told to look at it in one big picture. Did she pull the trigger or did she assist the person who pulled the trigger?" said Goodhart. "If you believe it either way, she is still guilty of capital murder."
DeGuerin countered: "Despite the goriness of this case, if you have a reasonable doubt, it is your oath and your duty to say not proved, not guilty."
After less than three hours, the jury returned a verdict.
Tiffany Koloroutis, Rachael's older sister, recalled the moment.
"I mean, your heart just starts racing," she said. "Mom grabbed my hand, and we were all sitting there. We thought, 'This is it.'"
'I Felt Like Justice Was Served'
As Ellis read the verdict, Paolilla broke down in tears.
"The state of Texas v. Christine Marie Paolilla," he read. "We the jury find the defendant Christine Marie Paolilla guilty of capital murder as charged in the indictment."
After the trial, Paolilla's parents struck a resigned tone.
"I couldn't move. I couldn't move," said Lori Paolilla. "It is nothing I would wish on anybody."
The Koloroutis family was pleased.
"I felt like justice was served," said George Koloroutis.
"It felt good," Ann Koloroutis said. "I didn't expect it -- that it would feel that good, but it actually did. It felt really good."
Soon after the verdict, George Koloroutis read a victim impact statement to the court.
"My daughter didn't die with a car wreck," he read. "She wasn't hit by lightning. She perished at the hands of two evil people, cold, calculating, heartless. I asked my wife what will hurt you most. Her picture never ages while we do, Christmas, birthdays, my daughter Tiffany's college graduation. There is always an absence, always a silence."
Adelbert Sanchez' sister, Nicole Sanchez, also read a statement. "As we come to a close to this chapter in our lives, we will walk away from this courtroom and forget about Christine," she read. "But Christine will think about the four precious innocent lives she brutally took that day, and the families that she destroyed, every day for the rest of her life."
The judge addressed the convict.
"Mrs. Paolilla, the jury having found you guilty of capital murder, the state having chosen not to seek the death penalty in this case, it's now my duty to sentence you to life confinement in the Texas Department of Criminal Justice institutional division," he said. "Do you have anything to say before I sentence you?"
Paolilla shook her head "no," breaking into tears.
Today Christine Paolilla, her high school's former "Miss Irresistible," is serving a life sentence at a women's penitentiary in Gatesville, Texas. Another school year is under way at Clear Lake High. And Rachael Koloroutis's family, like the families of the other victims, clings to memories of the child it's lost.
"We live as if she's still a part of us," said Tiffany Koloroutis. "And that's not going to change."
What drove Christine Paolilla to kill her friends? For Part 3 of the "Miss Irresistible" murders, visit the "20/20" Web site Friday. For the full story, watch "20/20" on Friday at 10 p.m. ET