Two teens have been charged in the brutal decapitation death of a registered sex offender in Michigan whose headless body was left to burn in a subdivision in what prosecutors are calling a "thrill kill."

Not guilty pleas were entered Monday in Romulus District Court for Jean-Pierre Orlewicz, 17, and Alexander James Letkemann, 18, on one count each of first-degree premeditated murder, felony murder and mutilation of a corpse in the death of 26-year-old Daniel Gene-Vincent Sorensen.

"A crime like this surprises us all," Wayne County Prosecutor Kym Worthy said at a press conference. "Any time anyone kills just because they want to — and that's what the evidence seems to suggest here — is bone-chilling. Why anybody would want to do that, especially being 17 years old, it makes us think and ask a lot of questions about our society."

Prosecutors allege the men lured Sorensen to the Canton Township home of Orlewicz's grandfather.

"They lured him in the garage where they prepared a space to kill him," Worthy said.

A tarp had been spread on the garage floor, and Sorenson was stabbed multiple times in the back. His head was sawed off and his body wrapped in the tarp, authorities said.

There, on a tarp they allegedly spread out for the attack, they slit Sorensen's throat with a knife and repeatedly stabbed him before cutting off his head with a hacksaw, prosecutors said.

They allegedly used a blowtorch on his hands and feet in an attempt to remove his fingerprints, officials said.

His torso was driven in a pickup truck and dumped in a Northville Township cul-de-sac where it was set on fire with gasoline. A utility crew found it the next morning, police said.

His head was dumped in the Rouge River near the border between Dearborn Heights and Detroit. It was found Saturday.

"They made plans on how they were to clean up the blood," Worthy said. "They made plans on how they were going to dispose of the body. No matter how malicious we all think it may be, it was very thought out and very methodical."

The investigation is continuing and involves other persons of interest, she said.

Raymond Cassar, Letkemann's attorney, urged the public not to rush to judgment.

"Especially on these two individuals. I understand this is a gruesome killing, at least according to the police report," he said.

James C. Thomas, Orlewicz's lawyer, would not comment on the case or the charges.

As Worthy's news conference was ending, officials in the Plymouth-Canton school district had memos hand-delivered to each teacher in the nearly 6,000-student high school complex where Orlewicz attended classes.

Orlewicz, of Plymouth, and Letkemann, of Westland, were arraigned via video Monday. Both were ordered held without bond.

"I want to put a face to these people," Sorensen's father, Jim, told MyFOXDetroit on Sunday. "And if it’s a friend I want to know who would call themselves friend and do this to my son."

Click here to watch MyFOXDetroit's report.

Police located Sorensen's truck on Friday abandoned at a Meijer parking lot in Westland, the station reports.

Sorenson was convicted in Tazewell County, Ill., when he was 17 of having sex with a 14-year-old girl, said Northville Township police Lt. Greg Rhodes. His troubled past had nothing to do with the murder, Worthy said.

The murder charges carry mandatory sentences of life in prison. Mutilating a corpse carries a maximum prison sentence of 10 years.

A preliminary examination is scheduled for Nov. 19 in 35th District Court in Plymouth.

Officials were tipped off over the weekend that one of its high school students possibly would be charged in the case, district spokesman Frank Ruggirello said.

"There are allegations in what looks to be a very brutal crime," he said. "The kids were talking about it. We wanted the teachers to talk to the kids about it."

Some students met Monday with crisis team counselors. Ruggirello said he expected more students would meet with counselors on Tuesday after details about the slayings were released.

The arrests and charges also were to be discussed during a staff meeting following Monday's classes, he said.

Cassar said Letkemann's family was not sure of what the charges would be until Monday's arraignment.

"This is a shock to them," Cassar said. "As in any family, they stand by his side."

Cassar said Letkemann's only other brush with the law was a charge of being a minor in possession of alcohol from a couple of years ago.

The Associated Press contributed to this report.