FARGO, N.D. (AP) — Attorneys in the case of a man accused in the killings of four people at a Mandan business are set to argue whether investigators followed the correct procedures in collecting evidence. The hearing Wednesday at the Morton County Courthouse comes 15 months after the stabbing and shooting deaths of four employees at RJR Maintenance and Management. Investigators say Chad Isaak carefully planned the gruesome killings, then tried to avoid detection by picking up shell casings, changing his clothing, and cleaning a knife and gun with bleach. But Isaak’s attorneys say authorities didn’t get proper search warrants and made false statements in the applications. They want much of the evidence thrown out.