Updated

The Latest on bodies found at a business in Mandan, North Dakota (all times local):

9:25 p.m.

Police in North Dakota say they've arrested a 44-year-old man in the slayings of four people earlier this week at a business in Mandan, near the capital city of Bismarck.

Mandan Police Chief Jason Ziegler says surveillance video identified a vehicle of interest and helped lead them to the suspect, who lived in the small town of Washburn about 35 miles (56 kilometers) north of Mandan.

Ziegler also revealed for the first time that the victims had been stabbed or shot.

Ziegler says a motive for the killings isn't yet known. He says the suspect lived in a trailer park managed by the business, RJR Maintenance and Management.

Ziegler says the man is being held on four counts of felony murder.

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This update has been corrected to show that police say the suspect lived in a trailer park managed by RJR Maintenance and Management, not owned by the company.

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6:55 p.m.

Police say they have detained a person of interest in the investigation into the killings of four people at a North Dakota business.

Mandan police said in a release Thursday evening that investigators are following up on a tip that led them to Washburn, about 35 miles (56 kilometers) north of Mandan.

Police released no further information and say it's an ongoing investigation.

The bodies of an owner and three employees were found early Monday at RJR Maintenance and Management in Mandan, just outside Bismarck. Police haven't said how they were killed or suggested a possible motive.

The North Dakota Bureau of Criminal Investigation and McLean County Sheriff's Office are also investigating the case.

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10 a.m.

Police have declined to release details of a 911 call that alerted authorities to the killings of four people at a North Dakota business.

The bodies of an owner and three employees were found early Monday at RJR Maintenance and Management in Mandan, just outside Bismarck. Police haven't said how they were killed or suggested a possible motive. They said they haven't identified any suspects.

The Associated Press requested audio and a transcript of the 911 call, but police denied the request Thursday, citing a provision of the state's open records law that allows authorities to withhold such information during an active investigation.

Police did confirm that a Wednesday search in a field about half a mile from the business was related to the investigation. They also created a 24-hour public tip phone line.

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6:40 a.m.

A combined memorial service will be held for a North Dakota business owner and three employees found slain earlier this week.

The service for Robert Fakler, William and Lois Cobb, and Adam Fuehrer will be held Tuesday morning at Bismarck Community Church.

Their bodies were discovered early Monday at RJR Maintenance and Management in Mandan, a city just across the Missouri River from Bismarck. Police have classified the case as a "multiple homicide," but investigators haven't said how the four died or identified the suspect.

Fakler co-owned the business, while the Cobbs and Fuehrer were employees.

Eastgate Funeral and Cremation Service director Bob Eastgate tells the Bismarck Tribune the families decided to have a combined service because the four were good friends.

The memorial service is open to the public.