Stern, who grew up with McAtasney and attended their junior prom with his alleged accomplice, 21-year-old Preston Taylor, was last seen at her home Dec. 2, 2016, the news station reported. Prosecutors allege that McAtasney strangled her there before enlisting the help of Taylor, his roommate at the time, to take her body to the Route 35 bridge, which spans the Shark River Inlet in nearby Belmar, and dispose of it over the side.

Stern's abandoned 1994 Oldsmobile 88 was found on the bridge hours later by police. The keys were still in the ignition, ABC7 reported.

The victim’s remains were never found. Authorities believe her body was carried from the inlet into the frigid waters of the Atlantic.

In this image taken from a Neptune City, N.J., police officer's dashboard camera early Dec. 3, 2016, an officer examines the vehicle belonging to Sarah Stern, 19, after it was found abandoned on the Route 35 Bridge in Belmar. Stern's friend and former classmate, Liam McAtasney, is on trial, accused of strangling Stern and throwing her body from the bridge. The 21-year-old McAtasney faces life in prison if convicted. Credit: Monmouth County Prosecutor's Office/The Asbury Park Press via AP Credit: Monmouth County Prosecutor's Office/The Asbury Park Press via AP

The key witness in McAtasney’s trial is Taylor, who has already pleaded guilty to his part in the crime. He faces up to 20 years in prison on charges of robbery, conspiracy, desecrating human remains, hindering apprehension and tampering with physical evidence.

ABC7 reported Taylor took the stand Wednesday and testified that McAtasney planned to kill Stern over about $8,000 he knew she had in her home.

Assistant Monmouth County District Attorney Meghan Doyle told jurors Wednesday that McAtasney believed the amount was more like $100,000 when he decided to kill his longtime friend and steal the cash, which Taylor testified Stern found in a shoebox, with a note from her deceased mother, at home her family was using for storage.

Taylor testified that McAtasney told him Stern had found the “type of money somebody would kill for,” the news station said. The plan was to get her drunk and steal the money.

Preston Taylor, 21, testifies Wednesday, Jan. 23, 2019, at the murder trial of Liam McAtasney at the Monmouth County courthouse in Freehold, N.J. McAtasney, also 21, is accused of strangling 19-year-old Sarah Stern, a longtime friend and former high school classmate, during a robbery Dec. 2, 2016, and throwing her body off a bridge. Taylor, who was Stern's date to their junior prom, faces 20 years in prison after pleading guilty to conspiring with McAtasney to rob Stern and helping him dispose of Stern's body. McAtasney faces life in prison if convicted. Credit: Patti Sapone /NJ Advance Media via AP Credit: Patti Sapone /NJ Advance Media via AP

"(We) specifically decided that Liam would strangle her," Taylor testified, according to ABC7. "Any other way, any type of weapon, would have been too messy, would have left a whole lot of evidence. And then as far as what to do with her after she was dead, we talked about a couple plans: bury her down at the campsite that Liam's dad owns (or) leaving her at the house."

They ultimately decided to make Stern’s death look like a suicide, Taylor said.

According to footage from the Asbury Park Press, Taylor testified McAtasney described, in detail, how he strangled Stern.

“It took quite a while for her to actually stop breathing, about a half hour,” Taylor said. “In the process, she beat herself, she vomited. When she started throwing up, he stuffed a scarf down her throat, and all the while, she said his name a couple times.”

Watch a snippet of Preston Taylor’s testimony below. In the second video, he describes during his 2017 plea hearing how he helped Liam McAtasney dispose of the body of their high school classmate, Sarah Stern.

McAtasney has denied involvement in Stern's disappearance or death, the news station reported. His defense attorney, Carlos Diaz-Cobo, told jurors during opening statements that they would hear from a witness who allegedly saw Stern walking away from her car the night it was left on the bridge.



The Asbury Park Press reported that Taylor previously told investigators McAtasney called him the night of the homicide and, after telling him he'd killed Stern, asked for help getting her body out of her house. Taylor allegedly told detectives he moved the body into some bushes and later went back with McAtasney to get it and load it into Stern's car, which one of them drove to the bridge.

NJ.com reported that Taylor also led detectives to two buried safes, one of which held some of the cash that was stolen from Stern.

Prosecutors are also expected to play for jurors a video in which an acquaintance secretly recorded McAtasney confessing to the killing.

Liam McAtasney, left, and Preston Taylor are pictured in their 2017 mugshots. Credit: Monmouth County Prosecutor's Office via AP Credit: Monmouth County Prosecutor's Office via AP

Stern's disappearance went unsolved for more than two months after her car was found abandoned, NJ.com reported. The break in the case came when McAtasney's acquaintance, previously identified only as A.C., contacted authorities and said he had information about what happened to her.

The acquaintance worked with investigators to record McAtasney making incriminating statements about the slaying. NJ.com reported that a prosecutor said during a February 2017 hearing that McAtasney told the acquaintance he strangled Stern with such force that he lifted her off the ground.

He also timed how long it took her to die, Doyle said at the time.

McAtasney and Taylor were among the people who searched for Stern over the months that she was still considered missing, NJ.com reported.

“It’s a gut-wrenching experience that no parent should have to go through. I love my daughter, and I just wish she would come home,” the victim’s father, Michael Stern, told the news agency as volunteers prepared to search for his daughter.

See Michael Stern’s Dec. 10, 2016, interview with NJ.com below.

Seen among the searchers in photos taken the day of Stern's interview are both McAtasney and Taylor.

Stern expressed disbelief after the two young men were arrested in connection with his daughter’s death. He knew both suspects and, when they and his daughter were growing up, often drove the trio to school.

"When I heard this, nothing made sense anymore," Stern said following the arrests, NJ.com reported.

He more recently talked about the loss of his only child and the anxiety of the upcoming trial.

"It's hard to put into words what the feeling is," Stern told NJ.com. "It's an overwhelming feeling of waiting and unknown expectations, and anxiety and everything else that goes along with it."

He said he did not know if a conviction in the case would offer any comfort.

“It may help, it may help,” Stern said. “Until that day, I do not know. I don’t know what my feelings will be.”