Federal prosecutors plan to appeal a ruling that overturned the death sentence for a Minnesota man convicted of kidnapping and killing a University of North Dakota student.

A jury in 2006 convicted Alfonso Rodriguez Jr., of Crookston, Minnesota, in the killing of 22-year-old Dru Sjodin, of Pequot Lakes, Minnesota. The same jury sentenced Rodriguez to death in the first and only federal capital punishment case in North Dakota.

Prosecutors filed a one-page notice Thursday with the 8th U.S. Circuit Court of Appeals that they were challenging the ruling by Judge Ralph Erickson, who oversaw Rodriguez’s trial and is now a member of the 8th Circuit.

Last year Erickson ordered a new sentencing phase for Rodriguez after ruling that misleading testimony from the coroner, the failure of lawyers to outline the possibility of an insanity defense, and evidence of severe post-traumatic stress disorder had violated Rodriguez’s constitutional rights.

Authorities said Rodriguez, a convicted sex offender, kidnapped Sjodin from the parking lot of a shopping mall in Grand Forks in 2003 and drove her to Minnesota, where he killed her and left her body in a field near Crookston.

Sjodin’s disappearance sparked days of massive searches, reshaped the way Minnesota handled sex offenders and led to the national sex offender registry being renamed for Sjodin. Rodriguez remains locked up at a federal prison in Terre Haute, Indiana.