A 16-year-old boy just home from school tried to do a good deed for his somewhat famous uncle, Steven Avery, and ended up raping and helping murder a young woman as the uncle looked on, prosecutors say.
The boy, Brendan Dassey, has detailed for investigators the final horror-filled hours of Teresa Halbach's life -- how she begged for help while shackled naked to a bed, how she was stabbed, strangled and shot and how the plot unfolded to burn her remains in a pit near Avery's rural home, according to a criminal complaint filed Thursday.
"I intend to hold each of these defendants accountable for the rape, torture and murder of Teresa Halbach," an emotional special prosecutor Ken Kratz said at a news conference. "There is a substantial amount of physical evidence that now makes sense, fits a lot of pieces together."
Dassey, who lives in a house near Avery's trailer at a family auto salvage yard near Mishicot in Manitowoc County, was charged with being party to first-degree intentional homicide, mutilation of a corpse and first-degree sexual assault. He is to make his first court appearance today in Manitowoc.
Avery, 43, was charged in November with first-degree intentional homicide, mutilating a corpse and possession of firearms by a felon. Avery, who was released from prison in 2003 after serving nearly two decades for a rape he didn't commit, has repeatedly denied any involvement in the killing of Halbach, 25.
Kratz said he expected to also charge Avery with sexual assault, false imprisonment and kidnapping.
The complaint Thursday detailed for the first time what allegedly happened to Halbach when she went to the Avery salvage lot Oct. 31.
Kratz said Avery called Auto Trader Magazine, gave a fake name and asked for one of its freelance photographers -- Halbach -- to visit the salvage yard to photograph a minivan that was for sale. She had been there several times before for similar appointments.
Kratz said investigators spoke with hundreds of people, including Dassey, at the beginning of the investigation. They talked to him again Monday and -- after discrepancies in his statement -- they interviewed him Wednesday and he told the story of his involvement.
According to the complaint, Dassey said he came home from school Oct. 31, picked up the mail and noticed a letter for his uncle.
Dassey said as he rode his bike to Avery's trailer, he heard a woman scream, "Help me."
The teen knocked on the door three times and Avery appeared covered in sweat, the complaint said.
Dassey said his uncle told him he sexually assaulted Halbach, he wanted to keep doing it and encouraged Dassey to assault her, too, the complaint said.
Dassey said the two went to Avery's bedroom where Dassey saw Halbach naked -- shackled to the bed with handcuffs and leg irons -- and begging for help, the complaint said.
Dassey said he raped a crying Halbach as she pleaded with him to uncuff her, to "tell Steve to knock it off" as Avery watched nearby, the complaint said.
Afterward, Dassey said he and Avery left the bedroom and watched television.
Dassey said Avery told him, "That's how you do it," the complaint said. Dassey stated that Avery told him he did a good job and he was proud of him.
Avery then stabbed Halbach in the stomach with a 6- to 8-inch kitchen knife and told Dassey to slit her throat, which he did, the boy told investigators. The uncle also told Dassey to cut some of her hair, the complaint said.
Halbach was still alive so Avery strangled her for two to three minutes, washed his hands, then punched her and told her to "shut up," the complaint said.
The two unshackled her, tied her up with rope and carried her to the detached garage, the complaint said. Avery then shot her about 10 times on the garage floor with a .22-caliber rifle, the complaint said.
Dassey said that Avery initially wanted to dump Halbach's body in a pond, but he changed his mind, the complaint said.
They then put her body in a fire-filled burn pit outside, adding tires and branches, the complaint said.
"Dassey stated that Steven Avery told him that he was glad Dassey had helped him," the complaint said.
The two also removed sheets from Avery's bed and Halbach's clothes and threw them into the fire, the complaint said.
They used gasoline, paint thinner and bleach to clean two areas of blood on the garage floor, Dassey told investigators.
Soon after, Dassey's mother called and told him to be home by 10 p.m., the complaint said.
Halbach's sport utility vehicle was found in the salvage yard, and bone fragments and teeth found in the burn pit were a DNA match to the woman.
Calumet County Sheriff Jerry Pagel said investigators were looking for more evidence Wednesday and Thursday in Avery's trailer and an outbuilding and removed portions of the garage floor for forensic testing.
Avery is in the Calumet County jail in lieu of a $500,000 bond. The 16-year-old was in custody at a juvenile detention facility. Avery's attorney, Dean Strang, didn't immediately answer an e-mail requesting comment.
Halbach's brother, Mike Halbach, who has been the family spokesman, didn't answer his cell phone Wednesday. A message said the family didn't want to comment given "the nature of the new information."