One of two northern Michigan men charged in the deaths of two women pleaded guilty to reduced charges Thursday and has agreed to cooperate in the prosecution of his co-defendant, prosecutors said.

Joshua Wirgau, 35, of Alpena, pleaded guilty to one count each of involuntary manslaughter and disinterment and mutilation of a dead body, accessory after the fact, prosecutors said.

A sentencing agreement requests 15-30 years in prison, prosecutors said.