Investigator suggests Mandan quadruple murder suspect killed 'for fun'

The prosecution on Friday, Aug. 13, alluded to the fact that Chad Isaak had no motive when he supposedly shot and killed four people at RJR Maintenance & Management in Mandan more than two years ago.

North Dakota Bureau of Criminal Investigation Supervisory Special Agent Arnie Rummel responds to a question asked by prosecutor Karlei Neufeld, right, during the trial of Chad Isaak in Mandan on Friday, Aug. 13, 2021. Rummel said he believes Isaak killed four employees of RJR Maintenance and Management in 2019. Jeremy Turley / Forum News Service
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MANDAN, N.D. — One of the lead investigators for the RJR Maintenance & Management quadruple murders in Mandan testified on Friday, Aug. 13, that he believes the suspect had no motive when he killed four people in 2019.

Arnie Rummel, supervisory special agent with the North Dakota Bureau of Criminal Investigation, said Friday that although it's beneficial to determine a suspect's motive in a homicide case, investigators aren't always able to do so. In some cases, a person kills another because they feel like it.

"Some people just kill for fun," Rummel said. "... I believe Chad Isaak killed those four people at RJR."

Isaak allegedly stabbed and shot Robert Fakler, Adam Fuehrer, William Cobb and Lois Cobb in Mandan's RJR Maintenance & Management building on April 1, 2019. Isaak pleaded not guilty, but if convicted, he faces the possibility of life in prison without parole.

For the first time since the murders occurred more than two years ago, the prosecution alluded to the fact that Isaak had no motive when he supposedly killed the four victims. The four victims were all employed at RJR Maintenance, and the property on which Isaak's mobile home was located in Washburn, North Dakota, was managed by the company.


When asked whether he was still confident law enforcement apprehended the correct suspect even though there is no apparent motive, Rummel said, "absolutely."

On Friday, investigators continued to outline the evidence they collected inside Isaak's mobile home that they believe connects him to the crime scene.

In the first hours of the investigation, law enforcement combed through security camera footage and discovered the suspect who they believed committed the crimes was wearing an orange hooded jacket, dark-colored pants, shoes, gloves and an orange face mask. In other videos, the suspect is seen wearing a dark jacket and what appeared to be a camouflage face mask.

Investigators found all those garments inside a dryer located within Isaak's Washburn mobile home.

In Isaak's freezer, Rummel said he found disassembled revolver parts in a plastic container, which smelled like bleach. Rummel testified that much of the mobile home smelled of bleach.

Defense attorney Luke Heck on Friday repeatedly pointed out that Rummel did not include that the mobile home smelled of bleach in his report of what occurred during the execution of the residence search warrant. Neither did many of the other investigators who searched the home, Heck stated.

Inside of a closet of Isaak's mobile home, BCI Special Agent Pat Helfrich said he found a sock that contained a box of ammunition and a baggie with spent bullet casings.

The ammunition discovered is consistent with the bullets used on the victims, law enforcement said. Nine bullet casings were found in the baggie, and Helfrich said he believed nine bullets were found at the crime scene.


During cross examination, however, defense attorney Bruce Quick pointed out nine bullets was not accurate.

On April 4, 2019, investigators executed search warrants of Isaak's pickup, chiropractic business and residence. Within his truck, law enforcement found "reddish brown" spots in multiple places. When investigators did an "on site" test, which provides preliminary results to determine if a substance is human blood, a swab of one of the spots tested positive.

They also found some orange fibers on various possessions in Isaak's truck, and the prosecution alluded that it could be orange fibers from the orange hoodie and face mask the suspect was wearing when the slayings occurred.

That evening, law enforcement also went to Isaak's chiropractic business in downtown Washburn, where they discovered rounds of ammunition inside a microwave.

On his desk, law enforcement found an open planner filled with the appointments Isaak had scheduled with his clients. They noted that on the morning of April 1, around the time the killings happened in Mandan, Isaak did not have any appointments scheduled, according to his planner. However, on cross examination, the defense pointed out that Isaak did not have any morning appointments scheduled for any of the days visible on the planner and often did not schedule morning appointments.

Alcohol, Tobacco, Firearms and Explosives Impression Analyst Allison Rees testified on Friday about some footprints found at the RJR Maintenance building near Fakler's body.

Rees analyzed the footprints to determine whether Isaak's shoes could have made the print, which were made in a combination of blood and egg yolks. Broken eggs were found near Fakler, who was stabbed 22 times, and witnesses testified that Fakler owned chickens and would often bring eggs to work for his co-workers.

Rees said that one of the footprints was the same size and had the same tread pattern as the shoe Isaak was wearing when he was detained on April 4.


The trial will begin its third and final week on Monday.

Readers can reach Forum reporter Michelle Griffith, a Report for America corps member, at

Michelle (she/her, English speaker) is a Bismarck-based journalist for The Forum of Fargo-Moorhead and Report for America, a national service organization that places journalists in local newsrooms to report on under-covered topics and communities.
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