Investigators searching for a missing woman found burned human remains at a salvage yard owned by the family of a man who spent 18 years in prison for a rape he did not commit.

Sheriff Jerry Pagel said authorities were working Thursday to identify the pieces of bone and teeth. Relatives of the missing woman, photographer Teresa Halbach, found her sport utility vehicle at the salvage yard on Saturday.

"It appears that an attempt was made to dispose of a body by an incendiary means; however, that attempt was not completely successful," Pagel said.

Pagel also said investigators found the key to Halbach's SUV in the bedroom of Steven Avery, whose family owns the salvage yard. Avery was freed from prison in 2003 after DNA evidence cleared him of a rape conviction.

Investigators found blood in Halbach's vehicle and in some buildings on the Avery property, Pagel said.

Halbach, 25, was last seen Oct. 31. She was on assignment for a magazine, taking pictures of cars for sale. One stop was at the Avery salvage yard near Mishicot, about 25 miles from Green Bay.

Avery, 43, was charged Wednesday with illegal gun possession. No one has been charged in Halbach's disappearance, and Avery has denied any involvement. He and his family have been ordered to submit DNA samples.

Avery was sentenced to 32 years in prison for sexual assault but was freed after a law school group persuaded a judge to allow new DNA testing, which linked another man to the crime.