By BLAKE NICHOLSON, Associated Press MANDAN, North Dakota (AP) — The co-owner of a North Dakota business where four people including her husband were slain says she and others don't know why the suspect would target anyone at the company. Chad Isaak, 44, a chiropractor in Washburn, faces four felony counts of murder in the April 1 deaths of RJR Maintenance and Management co-owner Robert Fakler and