A young drifter who went with a college student to his Manhattan apartment smothered him with a pillowcase, then settled in to watch the grisly horror film "Saw" to celebrate the killing, NYPD sources told FOXNews.com.

Jeromie Cancel, whom police and family describe as homeless and mentally unstable, allegedly confessed to the heinous crime, shouting at reporters that he killed 19-year-old Kevin Pravia "'cause I wanted to."

"Ya'll got problems with that?" Cancel yelled, smirking and chuckling as he was led away in handcuffs after his Tuesday night arrest.

But the NYPD said the suspect's motive was still unclear.

"He didn't confess to any motive," public information Officer Doris Otero told FOXNews.com.

Cancel, 22, was arrested late Tuesday on first-degree murder charges after hours of interrogation, Otero said. He has also been charged with second-degree murder.

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He allegedly stuffed a bag into Pravia's mouth and wound a TV cord around his neck before suffocating him.

He then rummaged through Pravia's DVD collection, choosing and watching the violent film "Saw" while Pravia lay dead on a bed nearby, sources said.

"He said that’s how he celebrated killing Pravia — sick, right?" a police source told FOXNews.com. "He stuffs a plastic bag in his mouth, wraps the electrical cord around, smothers him to death and sits down to watch a horror flick. ... Sick."

Cancel left before 11 a.m. the next morning with the Pace University honor student's iPod, laptop and cell phone, according to police. Investigators said that while he was being questioned in an unrelated case, he admitted killing Pravia and stealing the electronics.

Pravia, from Massachusetts, was found Sunday night by his roommate in New York City's Chelsea neighborhood. The sophomore was last seen being helped into a taxi early Saturday after a party.

Police said Cancel, who smiled for television cameras as he was being led in handcuffs out of a police station, was homeless. Police didn't know whether he had an attorney. He was arraigned at a Manhattan court on Wednesday.

Cancel's father, Jesus Soto, told FOX affiliate WNYW-TV that his son had stolen possessions from him in June, and he called police when Cancel showed up at his apartment Monday night, bragging and laughing about the crime.

"I'm so sorry," Soto said, choking back tears and shaking his head in disbelief. "I'm feeling myself the pain. This is not right. You don't take someone's life just like that."

The distraught dad told The New York Post that his son was "mentally imbalanced."

According to police, Cancel said Pravia approached him in New York's Union Square park around 6 a.m. Saturday looking for drugs, and the two went to Pravia's apartment a few blocks away.

No narcotics were found at the scene, police said. They told the Post they doubted drugs were involved.

It wasn't clear why the men went to Pravia's apartment.

"There was no indication of any sexual contact," a police source told the Post. Pravia fell asleep after the pair got home.

The medical examiner's office said tests were being performed to determine the cause of Pravia's death.

Cancel reportedly told investigators that after Pravia went to sleep, he decided to rob him, so he punched the student in the face before murdering him.

Police said he sold the laptop on the street after leaving the apartment, sold the cell phone in a store and couldn't remember what he did with the iPod.

Deputy Police Commissioner Paul Browne said authorities recovered the phone where it had been sold.

Pravia was from Peru, Mass., about 10 miles from the New York border.

Pace officials offered sympathy to the victim's family. Grieving friends quickly cobbled a Facebook page dedicated to the student, expressing shock over his death.

Pravia was a 2007 graduate of Wahconah Regional High School in Dalton, Mass., where counselors were available Tuesday for staff and students. Principal James Conro remembered him as a "quiet, polite and respectful young man."

"My heart goes out to the family," Conro told The Berkshire Eagle of Pittsfield, Mass.

Cancel's dad said his son should be punished.

"He deserves what he gets," Soto told WNYW-TV.

Click here for more on this story from MyFOXNY.com.

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Click here for more on this story from NYPost.com.

FOXNews.com's Jana Winter, Catherine Donaldson-Evans and The Associated Press contributed to this report.