David Jungerman, 80, of Raytown is charged with first-degree murder in the Oct. 25 shooting of Pickert outside Pickert's Brookside home.
Defense attorney Daniel Ross said Kansas City Police detectives have a practice of destroying written notes before the discovery phase of a trial. He also said recordings of 911 calls are not retained longer than six months. Ross asked that both the notes and the tapes be preserved so they may be available to the defense in preparation for trial.
The Jackson County Prosecutor's Office will respond to the motion. Another hearing was scheduled for June 15.
Jungerman has pleaded not guilty.
Police initially said he was not a suspect but later said they had found evidence of his involvement.