After hearing vivid descriptions of a brutal slaying, a Montgomery County jury found Jonathan Harris guilty of first-degree murder in the death of Main Line model Christina Carlin-Kraft in her Ardmore home in August.

Harris, 31, had confessed to the crime, telling police he repeatedly punched Carlin-Kraft, hard enough to break her sinuses, during an argument over cocaine that he said she refused to pay for after the two had consensual sex. He then choked her, he said, to keep her from calling police.

As he was led out of the courtroom late Thursday, Harris, of Johnstown, Pa., told reporters that he believed “justice was served" by the jury, whose verdict carries a mandatory life sentence.

Harris was also found guilty of kidnapping, possession of an instrument of a crime, and strangulation. The jury of eight women and four men deliberated for 5½ hours in Norristown.

After the verdict, Harris’ attorney, A. Charles Peruto Jr., said, "I really don’t feel like talking,” when asked about the resolution of the nearly week-long trial.

Assistant District Attorney Brianna Ringwood, the lead prosecutor, said Carlin-Kraft’s family was pleased with the verdict, which she called the “right result.”

“Ms. Kraft was a vulnerable person, and this defendant took advantage of that when he went back to her apartment and beat her and brutally murdered her,” she said.

Earlier Thursday, in her closing arguments, Ringwood portrayed Harris as a callous and calculated killer, and urged the jury to convict him of first-degree murder.

"Christina Kraft’s last moments on this Earth were horrendous, were horrifying, all because of the hardness of this man who sits before you,” she said. The pressure required to strangle Carlin-Kraft was more than 33 pounds, she said, adding that it would’ve taken Harris more than three minutes to kill her.

During his closing argument, Peruto implored jurors to decide the case “by the law and not emotion." He said that if they did so, they would find Harris guilty only of third-degree murder, because Harris did not have murder on his mind when he followed Carlin-Kraft back to Ardmore.

“This wasn’t a specific attempt to kill,” Peruto said. “He didn’t go there for that. There was no evidence of that whatsoever.”

Instead, Peruto suggested that Carlin-Kraft’s invitation to her condo was “a ploy to get cocaine for free,” and that the budding model was “rip-roaring drunk” when the fight broke out.

“This is not a whodunit,” Peruto said. “This was a ‘what was done and why.’”

He said Harris was high on cocaine, marijuana, and K2 during the encounter, and panicked when Carlin-Kraft wouldn’t stop screaming for him to leave. Harris’ repeated blows to her face and the strangulation were to keep her quiet, he added.

After the murder, Harris’ behavior — changing into Carlin-Kraft’s clothes and leaving her condo by jumping off a rear balcony — was the “mark of a man whose brains are scrambled.”

Ringwood told jurors that Harris not only was conscious in his actions, but also that he lied when he said the two shared cocaine inside the apartment. A medical examiner found only alcohol in Carlin-Kraft’s system at the time of her death.

“This man beat, bound, and strangled Christina Kraft in her home, and did so with intent, so that she couldn’t come into this courtroom to tell you what he did to her,” she said. “Everything he did was to silence that truth."

She also disputed Harris’ assertion in his statement to police that Carlin-Kraft was screaming inside the condo, saying none of her neighbors heard anything.

And the prosecutor placed particular emphasis on the statement Harris made to a man he shared a hospital room with after the murder and who testified this week that Harris told him, “There is nothing like squeezing somebody and feeling the last breath leave their body.”

“That statement says he was conscious and aware that she was taking her last breath,” Ringwood said. “It’s enough to convict him, and you should.”