Prosecutors argue Brendan Dassey's confession was "entirely voluntary" in a brief filed Wednesday in federal appeals court.
Dassey was convicted of several crimes in 2007 in connection in the 2005 death of photographer Teresa Halbach in Manitowoc County, including being party to first-degree intentional homicide, mutilation of a corpse, as well as second-degree sexual assault.
His uncle Steven Avery was sentenced to life in prison after being convicted of first-degree intentional homicide.
Prosecutors argue investigators clearly explained to Dassey that they could not make any promises. They say Dassey's claims regarding his confession leaves out the fact that investigators interviewed him "assuming he was just a witness." Prosecutors say the confession was voluntary because Dassey supplied most of the details in response to open-ended, rather than leading, questions.
Although Dassey "had low-average-to-borderline IQ," prosecutors say he was in "mostly regular-track high school classes."
The brief includes Dassey's graphic description of Halbach's rape and murder and refutes Dassey's claim that he got details he provided from a novel he had read.