A federal appeals court on Thursday blocked the release of Brendan Dassey, one of the subjects of Netflix’s “Making a Murderer,” from a prison in Wisconsin while the state appeals a judge’s decision to overturn his conviction on murder and sexual assault charges.

Mr. Dassey, 27, was to be freed by 8 p.m. on Friday from Columbia Correctional Institution in Portage, Wis., after a federal judge, William E. Duffin, overturned his conviction in August and ordered his release on Monday.

The United States Court of Appeals for the Seventh Circuit agreed to an emergency motion filed on Wednesday by the state Department of Justice to keep him behind bars until the appeal of his overturned conviction is settled, according to WBAY, a local TV station.

Mr. Dassey was found guilty in 2007 of participating in the killing of Teresa Halbach, a 25-year-old photographer, in Manitowoc, Wis. He and his uncle, Steven Avery, were both given life sentences in the case.