A man has been arrested in connection with a gruesome quadruple murder that left the owner and three employees of a North Dakota business dead. Chad Isaak, 44, is being held on four counts of Class AA felony murder. The victims were found dead Monday at RJR Maintenance & Management—a property management company in the city of Mandan. The victims were all shot or stabbed, according to police. Police Chief Jason Ziegler said Isaak’s car was identified at the scene by surveillance cameras and the suspect was arrested during a traffic stop Thursday. Isaak lives in a mobile home park managed by the RJR property management firm but police have not confirmed if that was part of the suspected motive. The dead included husband and wife Lois and William Cobb, 45 and 50 respectively. Their daughter, Briann Miller, told AP: “I’m left in the dark still. None of this makes any sense. All I know is my parents are gone.” The other victims were owner Robert Fakler, 52, and employee Adam Fuehrer, 42.