NIAGARA FALLS, N.Y. (WIVB) — The jury will start deliberating Monday whether Joseph Belstadt killed 17-year-old Mandy Steingasser back in 1993.

Friday afternoon, lawyers gave closing arguments and made their final attempts to convince the jury of what really happened in the early morning hours of September 19, 1993.

Closing arguments revealed two key points the sides disagree on: the timeline and the significance of two hairs found in his car.

What happened to Steingasser – is the question many have been asking for 28 years.

“It sounds gruesome, it sounds horrible, it sounds like something a psychopath would do, but it’s not Joe,” said defense attorney Michelle Bergevin.

“Mandy Steingasser was intentionally killed and that this man did it – that can be known,” said Niagara County District Attorney Brian Seaman.

Friday, prosecutors repeated that the last time Steingasser was seen alive was getting into Belstadt’s car.

The defense challenged that statement with a timeline that says Steingasser was seen later that night on the steps of a church. Belstadt maintains he dropped her off there.

“He didn’t do it. Couldn’t have, with that timeline. Think about the evidence and think about reasonable doubt and from their own witnesses, it doesn’t work,” Bergevin said.

Prosecutors say she was on the church steps before getting into Belstadt’s car. The difference in each side’s timeline of events is just a matter of minutes, but paint very different pictures.

Some of these things must remain unknown because this crime was not committed in front of eyewitnesses and the victim of this crime is not able to tell you exactly what happened,” said Seaman.

Another key difference is the explanation for finding two of Steingasser’s pubic hairs in the backseat of his car.

“Is there an innocent explanation for why those pubic hairs are in Joe Belstadt’s car, an innocent explanation, and the answer’s yes, because they can fall out,” Bergevin said.

She also said hairs can transfer from turning on an air conditioner or heater in a car, to explain how they could have gotten from the front seat where Steingasser was seen, to the backseat where the hairs were found.

Prosecutors assert these two pubic hairs show Belstadt tried to have sex with Steingasser in the backseat of the car. They suggest she didn’t want to, he got angry, and killed her.

“In this case, this young lady who was found with her pants forcefully opened had at least three pubic hairs that had been removed,” Seaman said.

Both sides also addressed Belstadt’s lie to police that he went to Canada after giving Steingasser a ride. He later went back to police and admitted to his lie.

Bergevin said he was just a nervous boy thinking he needed a witness to where he was. Prosecutors said the lie showed his need for an alibi and pointed to other inconsistencies in Belstadt’s statements.

Bergevin also mentioned the difficulty for witnesses throughout the trial to remember details from 30 years ago.

“The very age of this case creates reasonable doubt because of the poor recollection of the witnesses, the death of key witnesses, the inability for you to really know what happened,” she said.

The jury will be charged on Monday morning and will begin deliberating right after.

If convicted Belstadt faces life in prison.

Kayla Green is a reporter who has been part of the News 4 team since 2021. See more of her work here.