NEPTUNE CITY - As a New Jersey State Police helicopter buzzed overhead, Michael Stern stood with his hands in his pockets, braced against the bitter wind, looking out over the Shark River and trying to process why he was there.

"Please let them find her. Please let them find her," he repeated in his head.

A day after Monmouth County authorities announced the arrests of his 19-year-old daughter's alleged killer and accomplice, the search resumed Friday morning for her body, which investigators say was dumped over the side of the Route 35 bridge in Belmar two months ago.

Charged in her death are two of Sarah Stern's longtime friends, Liam McAtasney and Preston Taylor, both 19 of Neptune City.

Stern said he's still trying to process how two friends his daughter knew since grammar school could possibly be involved in her death.

"When I heard this, nothing made any sense anymore," he said.

These were boys who Sarah grew up with. He often drove them to school. He gave them candy when he played Santa Claus for their school. He entertained them when he played Clifford the Big Red Dog in other school events, he said.

Taylor took Sarah to the junior prom, he said.

Since his daughter's disappearance on Dec. 2, Stern said he held out hope that maybe she just wanted some time away. Investigators floated other theories - that she committed suicide, she was abducted or she ran away.

When detectives told him Wednesday night that Sarah was dead, Stern said he wasn't prepared to hear those words. Her death still is incomprehensible to him. At least for now, without finding her, he said.

"It was better with Sarah being missing. Maybe she had left without telling anybody. Maybe she just wanted to get away," he said. "I didn't think she was killed, murdered. It's just a horrible thing to hear."

Monmouth County Prosecutor Christopher Gramiccioni said McAtasney strangled Sarah Stern on Dec. 2 at her Neptune City home while he robbed her of thousands of dollars. He said Taylor - at McAtasney's request - helped dump her body over the side of the Route 35 bridge into the Shark River in Belmar early the following morning.

McAtasney is charged with murder, felony murder, conspiracy, hindering apprehension and desecration of human remains. Taylor is charged with conspiracy, hindering apprehension and desecration of human remains. Both are being held in the Monmouth County jail pending detention hearings in the coming weeks.

"Without physically finding Sarah, it's still difficult for me to process all this," Stern said. "It's a hard thing to go through. None of it makes any sense."

Stern grew up in the same community and attended Neptune High School with McAtasney and Taylor, according to school records.

Graduating in 2015, Stern played softball and was on the swim team while McAtasney was on the school swim team and Taylor was on the track-and-field team, the records show.

MaryAnn Spoto may be reached at mspoto@njadvancemedia.com. Follow her on Twitter @MaryAnnSpoto. Find NJ.com on Facebook.