Law enforcement officers responding to a 9-1-1 call yesterday morning found four people dead at a North Dakota property management business, news sources report.

The victims who were discovered at RJR Maintenance and Management have been identified as 52-year-old Robert Fakler, 42-year-old Adam Fuehrer, 45-year-old Lois Cobb and her husband, 50-year-old William Cobb. Fakler was the owner of the business in Mandan. The others were his employees, authorities said.

Mandan Police Chief Jason Ziegler said at a press conference that investigators believe the deaths are an isolated incident, and not part of a larger threat to public safety. Ziegler did not disclose causes of death or identify a person of interest.

Business owners and residents in the area are being asked to contact investigators with video footage or eyewitness accounts.

According to its website, RJR Maintenance and Management is a family-owned company that has been in business for more than 20 years. Mandan has a population of 22,000 and is six miles west of Bismark.