Mike Peterson's lawyers are asking that the district attorney's office and Durham police turn over notes and witness statements that could show inconsistencies in the prosecution's case.
Reading over the motion, WRAL has also learned the police questioned Peterson's ex-wife about the death of a family friend in 1985.
An autopsy report states Elizabeth Ratliff had a rare blood disease and died from a brain hemorrhage. The report also says she was found at the bottom of the stairs with several deep cuts in her scalp.
Last December, Peterson's wife, Kathleen, was found at the bottom of the stairs in the couple's Durham mansion.
One of Peterson's lawyers says there is no connection whatsoever between the cases.
The defense also wants the phone records of all calls made from the Peterson mansion the night Kathleen died. In the autopsy report, there is reference to the fact that Mike Peterson may have placed other calls before dialing 911.
In Friday's motion, the defense says the phone records prove otherwise.
District attorney Jim Hardin was not available for comment Friday. Peterson is scheduled to be in court later in May for a procedural hearing.