DARLINGTON, Wis. -

Armin Wand III has pleaded guilty to three counts of first-degree intentional homicide, one count of first-degree attempted homicide, one count of arson, and one count felony murder in a plea deal announced Friday.

The Argyle man is accused of starting a fire last September that killed his three children, ages 3, 5 and 7, as well as his unborn child.

His wife, Sharon Wand, and their 2-year-old daughter survived the fire.

Sharon Wand was pregnant at the time of the fire. The charge of felony murder is for the death of her unborn child.

Two attempted homicide charges were read in but dismissed as part of the plea deal.

In addition, Armin Wand will testify against his brother, Jeremy Wand.

Prosecutors said Jeremy Wand, Armin's brother, conspired with his Armin Wand on setting the fatal fire for the promise of $300. He's scheduled to appear in court for a status conference Wednesday.

Wand is facing maximum of three life sentences, 60 years for the attempted homicide charge, 40 years for the arson charge and 15 years for a felony murder charge.

“This is certainly one of the most serious crimes I've ever had to deal with, and it might be fairly obvious what the state might be recommending,” assistant district attorney Roy Korte said.

Wand told the judge he wants to accept responsibility, save the county money, and save Sharon Wand from testifying in court. The prosecution gave similar rationale for why accepting the agreement was a better option for the state than proceeding with the trial.

Wand acknowledged in court that he could be in jail until he died.

Earlier this week, a judge ruled that part of Wand’s confession to police could not be submitted as evidence in the case. While that decision was a contributing factor, defense attorney Guy Taylor said it was not the sole reason for entering a plea agreement.

“Even if we had prevailed on all of our arguments,” Taylor explained, “there was still evidence that the state had available to them that would have been pretty strong evidence.”

Sharon Wand would have testified in her soon-to-be ex-husband’s trial if it had moved forward. Korte has been in constant contact with Sharon throughout the proceedings.

“Sharon is certainly ready to testify. She does not relish in the prospect of having to do so. She's still healing physically, she's healing mentally,” Korte said, “and I'm sure she will be relieved that at least in regards to this case, having to testify against her husband, or soon-to-be ex-husband, she won't have to do that.”

Korte said Sharon Wand is improving, but is likely mourning her sons and unborn child every day.

Wand’s sentencing is scheduled for April 17.

The Wisconsin Department of Justice announced the court hearing a few hours before Friday’s hearing in Darlington.