Iowa’s Attorney General has filed an appeal of a federal court ruling that ordered that a man convicted of murder in Black Hawk County in 1976 be retried or released.

Federal District Court Judge Donald O’Brien issued the order August 31st in the case of Jerry Mark. Mark was convicted in the shotgun killings of his brother Less, sister-in-law Jorjean Mark, and their five year old daughter and 18-month-old son in November 1975 on their farm northeast of Cedar Falls.

Prosecutors said Jerry Mark, who is now 63, drove from California to Iowa to kill his brother and family in a disagreement over inheritance of the family farm. In his ruling Judge O’Brien says there’s doubt about the forensic evidence used to convict Mark after the evidence was reviewed using new scientific methods.

The appeal was filed with the 8th Circuit U.S. Court of Appeals in St. Louis. A new release on the appeal from the Attorney General says the process will take eight months to a year or more. Mark will remain in prison at Ft. Madison during the appeal.