MILBANK, S.D. (KELO) – A Milbank murder suspect plans to change his plea and receive his sentence tomorrow.

57-year-old Brent Hanson is expected to plead guilty to three counts of first degree murder after killing his brother, sister-in-law and unborn niece in December of last year. In exchange, three charges of second degree murder will be dropped, and he will no longer face the death penalty.

Clyde and Jessica Hanson with their son.

According to court documents, Brent Hanson killed his brother Clyde with a baseball bat on December 12. The next morning, he killed his pregnant sister-in-law, Jessica, with a machete.

Now, Jessica’s family is speaking out against the plea agreement.

Clyde and Jessica Hanson would’ve celebrated their sixth wedding anniversary this week. Instead, their now three-year-old son is left without parents or a baby sister. When Jessica died, she was nine months pregnant with a baby girl — who she planned to name Annika.

“They were just beautiful people. And I don’t want them to be forgotten,” Jasmine King, Jessica Hanson’s sister, said.

King will remember her sister as a loving and caring person.

Clyde’s brother Brent has reached a plea agreement with prosecutors.

King says her family didn’t know about the deal until it was already signed.

“We were just so taken back, we didn’t have enough time to process that. The only thing we could say is ‘no, we want a trial, we want a trial.’ And he said, ‘it’s too late, it’s been accepted and the sentencing is going to be on Tuesday,” King said.

Under this plea agreement, if Hanson pleads guilty to three counts of first degree murder he will face a mandatory sentence of life in prison without parole.

King says that isn’t the justice she was hoping to get for her younger sister.

“He’ll get to be in prison, enjoying meals, having recreation time. He’ll get to go to school. And he won. He won. He got what he wanted, he ended my sister’s life and he’s going to live in prison,” King said.

King and her family have now sent letters to the judge, asking her to reject the agreement.

“I feel like the state attorney did not have our best interest at heart,” King said.

KELOLAND News reached out to the Grant County State’s Attorney, but he declined to give a statement about this plea agreement.

In a factual basis statement signed by Brent Hanson, he admitted to having a premeditated plan to kill Clyde, Jessica and their unborn child. He also admitted he was not acting in self-defense when he killed them.

A psychiatric report found Hanson was competent to go on trial.

We are heartbroken with the State’s Attorney’s brash decision to enter into this plea agreement without the knowledge nor approval of the family. We are displeased with the State’s Attorney as we had clearly stated to him that we wanted a trial for Jessica, Clyde and Annika Hanson and made it clear we were seeking justice in the form of the death penalty. The State’s Attorney’s decision to enter into this plea agreement is not an appropriate punishment in light of the charges and actions of Brent Hanson. In our eyes, the State’s Attorney sided with the Defendant by giving him his life back while our family continues to grieve over the stolen lives of our loved ones with no peace in sight.

Full statement from Jessica Hanson’s family: