KUSA - A man who killed and dismembered a Denver teenager was sentenced to life in prison without the possibility of parole Tuesday morning. Edward "Tim" Romero was found guilty of first-degree murder in early February.

Romero had pleaded not guilty by reason of insanity in connection with the death of 16-year-old Alicia Martinez. Her body was found in a home in Denver in October 2010 following a house party.

February's first-degree murder conviction made Tuesday's sentencing outcome certain. The judge had no other choice but to hand down a life sentence to Romero, who remained emotionless throughout the hour-long hearing.

"Never in my life did I know sick people like you roam the streets," a tearful Vanessa Martinez said during the sentencing hearing. Vanessa Martinez, the teen's mother, said she has forgiven Romero because of her faith, but cannot easily remedy in her mind the insanity defense.

"He was faking it the whole time," she said after the hearing when asked about Romero's odd behavior at trial.

It was a sentiment that was echoed by Denver prosecutor Henry Cooper on Tuesday. Romero, he said, "pretended to be insane" during the course of the trial.

At trial, Denver prosecutors outlined the case against Romero and went into great and oftentimes gruesome detail as to what Romero did to the Alicia Martinez's body after twice shooting the teen in the face. The dismemberment, they said, was done to conceal the crime.

Judge William Robbins called it "as horrible a case, I think, as I have ever seen."

Antoinette Paniagua, Alicia's stepmother, said the dismemberment robbed the girl's father of a traditional open-casket funeral service. Jesus Paniagua is originally from Mexico.

"That was incredibly difficult, and that's something that's always done in Mexico. That's all he had known," Antoinette Paniagua said. "He was left wondering what was inside, and more importantly what wasn't inside."

Romero's defense did not try to deny that he committed the crime. Instead, they argued at trial that Romero had a long history of suffering blackouts - periods of time his friends and family called "episodes."

Romero said he suffers from disassociation identity disorder, a controversial diagnosis with plenty of skeptics within the mental health community.

Francesca Pagliasotti, who was Romero's girlfriend, is serving a 10-year sentence after being convicted of charges including being an accessory to murder. Prosecutors said she helped clean up the crime scene.

Another woman who prosecutors said took Martinez to the party pleaded guilty to contributing to the delinquency of a minor.