He was also charged with being party to the crimes of attempted escape and taking a hostage without bodily harm, following a failed escape attempt from Wisconsin’s Outagamie County Jail on June 7.

Beyer had been arrested and booked on June 5.

Matthew Beyer, 35, was formally charged with two counts of first-degree intentional homicide Wednesday, nearly four months after the deaths of his two biological children

William Beyer, five (left), and Danielle Beyer, three (right), were found dead in their mother’s home on February 17. Autopsies showed they’d suffered stab wounds in the head and neck

William and Danielle were found dead by police, in their bedroom on the upper level of a duplex in Kaukauna, Wisconsin, at about 7am on February 17.

Police met the children’s biological mother, Melissa Schuth, who they lived with at the top of the stairs, before going into their bedroom, according to the criminal complain, the Appleton Post-Crescent reported.

An officer said that William was found on the floor between the children’s two beds, while Danielle was still in her bed. She was partially covered by blankets.

No signs of forced entry were seen. Schuth told investigators that she, her new husband and the two children were the only people at the home the night before the children died.

According to the criminal complaint, autopsies found that Danielle had five ‘sharp force injuries’ to her neck, while William had eight to his head and neck. William also had two cuts on this fingers.

One of the officers described the injuries as ‘almost a hole’ in their necks.

Prosecutors suggested that the hand wounds indicated William tried to fight off their attacker,

Action 2 News reported.

Beyer appeared in court on June 10 (pictured) and was given a $2.5million bond for the homicide charges, as well as an attempted jailbreak on June 7

A friend of Beyer’s new wife told investigators that Beyer (pictured) was upset about having to pay child support while not seeing William and Danielle often

In court Wednesday, Wisconsin’s Outagamie County District Attorney Melinda Tempelis said that the allegations were that Beyer – William and Danielle’s biological father – ‘stabbed both children in the neck in the middle of the night, killing them both.’

She described the deaths as being ‘extremely brutal, very awful homicide’ and noted that authorities believed the children died ‘almost immediately’ after the attack, according to the Appleton Post-Crescent.

When notified about the death of his children, the detective said that Beyer had ‘very little initial emotional response.’

According to the complaint, the detective had ‘done many death notifications and found (Beyer’s) lack of emotion extremely unusual, especially because the death notification was about his two children,’ the Appleton Post-Crescent reported.

While being interviewed on February 17, Beyer allegedly told police that he wasn’t able to sleep that night. Instead, he’d whiled away the time rolling cigarettes and playing on his cell phone.

He also supposedly said he’d stopped driven his silver 2006 Chrysler Town and Country minivan to the gas station in Manitowoc at 4.45am on his way to work in Two Rivers, Wisconsin.

Police said that Beyer told them he hadn’t been to Kaukauna in two months. The two cities are about an hour’s drive apart.

Surveillance video from the gas station showed that he had stopped to buy $20 of gas and put air into his car’s tires. He then clocked in to work at 5am, according to the complaint.

During the interview, police said they noticed Beyer’s clothes were ‘very dirty’ and that he had grease and cuts on his hands and a scratch on his forearm. Beyer allegedly said he sustained the injuries while at work that day.

During the investigation, one of the children’s neighbors said that they had seen a silver minivan parked a block away from their home at about 3am on February 14. The neighbor said that a skinny man wearing dark clothes and a stocking cap exhibited the car, walked around the block, returned to the car and drove off.

Traffic camera footage showed a silver minivan leaving Beyer’s home in Manitowoc at 2.19am and returning at 4.23am on February 14, the complaint said.

During an interview with police, Beyer said that he had a ‘bad feeling’ that something was going to happen to Danielle (left) and William (right), so he had gone to check on them

Danielle (left) and William (right) were described in their obituary as being ‘inseparable’

Beyer and the children’s biological mother, who they lived with (pictured with new husband Tyler Schuth), were in the midst of a custody battle

Police arrived at Schuth’s home (pictured) on February 17 at 7am and found the children dead in their bedroom. Beyer admitted to using a ‘card’ to enter the house earlier in the day

Police also used home surveillance video to determine that a silver minivan, which has distinctive details, left Beyer’s home address at about 1am on February 17 – the day the children died – and traveled in the direction of Kaukauna.

Surveillance showed the same car traveling away from the children’s home at 3.10am and arriving back at Beyer’s home address at 4am.

The complaint noted the minivan ‘avoided all major intersections and main roads in Kaukauna and did not take the most direct route out of Kaukauna.’

When re-interviewed on June 4, Beyer said that he’d driven through Kaukauna, but tha he hadn’t stopped in the city. Eventually, however, he admitted that he had going to the city multiple time before and on the day of February 17.

Beyer allegedly told police that on February 14, a ‘bad feeling’ led him to believe that ‘something bad was going to happen to one of his family members’ and that was why he’d driven to Kaukauna to check on his children.

He supposedly claimed that he had only walked around the block and hadn’t gone inside the home.

He also said the same ‘bad feeling’ returned on February 15 and that he had driven to Kaukauna again at about 1am and parked the van across the street from his children’s home. Again, he claimed that he didn’t enter the property.

In the end, Beyer allegedly told police that on February 17, he went inside the children’s home, using ‘a card, a blue one, a library card, I think’ to enter the home.

He said that he saw the children were in their beds, asleep, and that their night light was on.

During his interview, Beyer said that he had a collection of decorative knives and that one with a two-to-three-inch blade was missing. He was also able to identify a photo of a knife that his new wife claimed was missing.

A friend of Beyer’s wife claimed to police on June 10 that while talking about who might’ve killed Beyer’s children, Beyer had described how he could have killed them, without their being able to cry out, in graphic detail.

The friend also said that Beyer had been upset about having to pay child support for them because Schuth wouldn’t let him see the kids and that he ‘did not even believe he was the father,’ according to the complaint.

A family court document, reviewed by the Appleton Post-Crescent revealed that Schuth claimed Beyer periodically claimed the children weren’t his and that they had argued over where to exchange the children.

The relationship between Schuth and Beyer was said to be ‘very strained.’

The family court case was set for a review hearing on February 17 – the same day the children died.

Beyer was arrested on June 5 and charged with attempting to escape from jail two days later.

The criminal complaint stated that Beyer’s fellow inmate, Demetrius Williams, was able to surprise a jail guard during a cell check and restrain her, while threatening her with a sharpened pencil

Williams then supposedly insisted that Beyer would be escaping with him and ordered her to open Beyer’s cell door. She was able to trick Williams by pressing a button to open a different cell door and escaped his hold and get help.

It’s unclear if Beyer ever left his cell, but he allegedly told investigators that he thought Williams was hoking with his escape plot, but had seen the man putting 20 freshly sharpened pencils around the cellblock.

Williams was in jail, charged with 1st Degree Intentional Homicide, Attempted 1st Degree Intentional Homicide and Attempted 1st Degree Intentional Homicide of an Unborn Child and was being held on a $2million bond, which was increased by $500,000 to cover the attempted escape, according to

NBC 26 .

While setting Beyer’s $2.5million bond, the judge said that ‘Quite frankly, under the circumstances, Beyer is a dangerous person.’

If convicted of the first-degree intentional homicide charges, Beyer will be given a mandatory life sentence.

Beyer made a remote appearance in court on June 10 from Outagamie County Booking, according to

NBC 26 . He is due back in court on July 30 for a preliminary hearing.

A joint obituary for Beyer’s two children said that they ‘were inseparable’ and noted that Will was Dani’s protector and Dani always looked up to Will. They were both always smiling with their great big smiles and were just happy to always be together.’