New Jersey police have arrested two men in the presumed strangulation death of 19-year-old Sarah Stern

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Liam McAtasney stands accused of doing the unthinkable: robbing and strangling his childhood friend and dumping her body into a river near her home.

In court on Tuesday, prosecutors gave more details of the alleged crime, laying out the horrific details of 19-year-old Sarah Stern’s presumed death.

Monmouth County assistant prosecutor Meghan Doyle alleged that McAtasney, 19, told a witness that he had choked Stern and watched her die for “about 30 minutes.” Doyle alleged that the witness, identified in court only as A.C., recorded the conversation.

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Liam McAtasney

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Doyle also alleged that McAtasney told the witness that “he had planned it for weeks leading up to Sarah Stern’s death.” She also alleged to the judge that McAtasney enlisted a friend, Preston Taylor, also 19, to help dispose of the body in the Shark River. Stern has never been found.

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But a lawyer for McAtasney insists that his client had nothing to do with Stern’s disappearance. “He is completely innocent,” attorney Charles Moriarty tells PEOPLE. “He didn’t do it.”

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Preston Taylor

Moriarty also says that there’s no proof that Stern is even dead. “I hope for everyone’s sake that she’s still alive,” he says. “Because my client had nothing to do with it.”

After court on Tuesday, Moriarty reiterated the claim that Stern could still be alive. Speaking to reporters, he said that his client’s alleged confession was merely “locker room talk,” and noted that McAtasney was calm as he discussed her death, “like they’re talking about going to dinner.”

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Sarah Stern

Moriarty further told reporters that his client now maintains his innocence — despite anything he may have said.

“He indicated to me that whatever was said, he had nothing to do with this. He wouldn’t hurt anyone, and he didn’t hurt her,” Moriarty said.

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Both McAtasney and Taylor are being held without bond. Neither has entered a plea.

An attorney for Taylor did not return PEOPLE’s call for comment.