Waukesha man accused of killing parents, living with decomposing bodies pleads guilty in court

Updated: Jan. 8, 2026

WAUKESHA, Wis. (CBS 58) -- A Waukesha man accused of killing his mother and stepfather inside their home last year pleaded guilty in court Thursday morning, Jan. 8.

Just two months ahead of trial, 18-year-old Nikita Casap entered a guilty plea on two counts of first-degree intentional homicide. The other seven charges Casap was facing will be dismissed in exchange for this plea deal.

Back in February of last year, investigators were called to Casap’s home on Cider Hills Drive for a wellness check after no one had heard from the family in two weeks.

Investigators found Donald Mayer and Tatiana Casap inside the home, covered in blankets and clothing. Their bodies had been decomposing for at least two weeks.

Casap was arrested in Kansas, along with a gun, cash, jewelry, and the family’s dog.

“I believe he’s a danger to the community. The facts of this case, which will be further explained at the sentencing – I just think he’s a danger to our community,” said Lesli Boese, Waukesha County district attorney.

A federal investigation into Casap revealed ties to an extremist neo-Nazi group and a plot to assassinate President Donald Trump. The Waukesha County District Attorney’s Office says it's unclear if federal charges will be filed.

“Certainly, I don’t think he should be out in the community, and I would argue against that,” said Boese.

Boese says while she was surprised Casap pleaded guilty, she believes avoiding a trial is the best option for the victims’ families.

“I guess I'm a little surprised. I mean there’s really no downside for him to take it to trial, but again, I think the courts look at the fact that someone takes responsibility for what they did, and I think that’s a factor they consider at sentencing,” said Boese.

Casap will face life in prison, but he could be eligible for parole after serving 20 years on each count.

Boese says she will push for Casap to be denied any chance at parole during his sentencing. That’s set to take place March 5.

Published: Jan. 6, 2026

WAUKESHA, Wis. (CBS 58) -- A Waukesha teen accused of killing his mom and stepdad is expected to plead guilty. 

Eighteen-year-old Nikita Casap is accused of shooting and killing Donald Mayer and Tatiana Casap inside their home last year. 

According to court documents, Casap intends to plead guilty to first degree intentional homicide. 

He's expected in court Thursday, Jan. 8, for a plea hearing. 

The plea change comes two months before the case was expected to go to jury trial. 

Casap faces life in prison without the possibility of extended supervision.