Calumet County District Attorney Ken Kratz refused to say Monday whether investigators were focusing on Avery or anyone else.

Manitowoc County District Attorney Mark Rohrer appointed Kratz special prosecutor in the case Monday because he wants to avoid the appearance of impropriety.

Avery sued Manitowoc County over his wrongful conviction, and he has said he fears someone is trying to set him up as a suspect in Halbach's disappearance. Avery has said he has nothing to hide.

Kratz said investigators have a significant amount of evidence in the case, though authorities released few details about the investigation Monday.

He said investigators executed a number of search warrants on the Avery property as well as in other counties, including in Marinette County, where Avery's family has a cabin. Some search warrants were issued for properties not connected to the Avery family, he said.

Avery's attorney, Walter Kelly, has said he is confident his client had nothing to do with the woman's disappearance.

Calumet County Sheriff Jerry Pagel said people who were searching for Halbach stopped at the Avery salvage yard near Mishicot on Saturday, got permission from a family member to look around and found her vehicle.