There is an evidence dispute in the case against the man accused of killing his estranged wife and her 11-year-old son.
Cutis Lopez, 45, wants a judge to bar prosecutors from using his cellphone records.
Authorities used those records to trace his movements between the time Jane McQuain was last seen in October and the night her body was found beaten and stabbed to death in her Germantown home.
Authorities allege that Lopez, 45, is responsible for her murder and the murder of her son William in Montgomery County.
Lopez is charged with two counts each of murder and kidnapping and one count of robbery.
Lopez was arrested in North Carolina in mid-October, just days before William's body was found in the woods in Clarksburg.