FREEHOLD, N.J. (CBSNewYork/AP) — Prosecutors say man accused of killing a woman during a robbery told a friend that he strangled her with such force that he lifted her off the ground and watched for 30 minutes as she died in her home.

The details emerged Tuesday during a hearing where a judge ruled that 19-year-old Liam McAtasney will remain jailed until his trial.

Prosecutors told the judge that the Neptune City man watched the clock as Sarah Stern was dying. They say he gave the description of the killing to a friend, who secretly videotaped their meeting.

“This defendant admitted to murdering Sarah Stern with his own hands and choking her, he even so much as demonstrated how he lifted her up off of the ground, then left her on the floor and watched her die for 30 minutes,” Assistant Prosecutor Meghan Doyle said. “He knew exactly how long it was because he chose to time that.”

Authorities say McAtasney recruited Preston Taylor to help him dump her body.

“The defendant goes back to Sarah Stern’s home after leaving her dead body there for a duration of approximately eight hours, removed her from her premises with the co-defendant and brought her to the Belmar Bridge, where he, along with the co-defendant, dumped her,” Doyle said.

Stern’s body has not been found. Taylor also is charged in Stern’s death and a judge ruled last week that he, too, will remain in jail until his trial.

Sarah Stern

Sarah Stern was last seen alive Dec. 2, 2016 at her Neptune City, New Jersey home. (Photo credit: Monmouth County Prosecutor’s Office)

McAtasney’s attorney, Charles Moriarty, did not fight prosecutors’ bid to keep his client in custody, but told reporters after the hearing that McAtasney was innocent.

“My client indicates he has nothing to do with this and he really hopes that the girl is alive. The last time he saw her, she was alive,” he told reporters, including CBS2’s Meg Baker. “There is a videotaped statement that the prosecutor talked about, which is unusual in the sense that both boys, Preston and my client, seem to be talking like they’re going out to lunch or something. It’s like some story that they made up. Whether or not that’s accurate or not, I can’t tell you.”

The attorney went so far as to suggest that Stern may have run away or committed suicide. Her body has yet to be recovered.

But Stern’s family is having none of that.

“To imagine something like this is just unfathomable,” the family’s lawyer and longtime friend Charles Stone said.

The men were both longtime friends of Stern’s and Taylor was her junior prom date.

Both defendants were among the nearly 100 people who volunteered to help search for Stern in the area surrounding the Shark River inlet after her car was found the same day she went missing.

McAtasney faces charges of murder, felony murder, conspiracy, hindering apprehension and disposal of human remains. Authorities allege Stern was killed during a robbery that McAtasney had planned for several months.

Taylor has been charged with conspiracy, hindering apprehension and disposal of human remains for his alleged role in the crime.

Taylor’s attorney, John Perrone, has said that Taylor tried to talk McAtasney out of killing Stern. Prosecutors say they have no evidence of that.

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