New details are unfolding in the RJR quadruple murder case. Little information has been made public at this point, but Mandan Police, the North Dakota Bureau of Criminal Investigation and the McLean County Sheriff’s Office have worked together to follow up a lead that led them to Washburn.

A person of interest has be detained for questioning. The investigation is still on going.

Washburn is located roughly 40 miles north of Mandan and has a population of nearly, 1,400 people according to the city's website.

We will update this story as more information becomes available.

**** UPDATE posted April 5, 10:45 a.m.  ****

Police have arrested Chad Isaak of Washburn and are holding him on four counts of AA felony murder. Surveillance cameras identified Isaak's car as being at the scene of the shootings, officials said. Investigators later located the vehicle in Washburn.

Isaak was arrested during a traffic stop Thursday night. Police Chief Jason Ziegler said evidence in the vehicle gave investigators enough probable cause to make an arrest. Isaak is being held at the McClean County Jail. He is scheduled to make an appearance in court Friday.

Police have still not released the cause of death, but they have confirmed that the victims were either shot or stabbed.

Police have said a motive for the killings is not yet clear. Isaak lives in a mobile home park managed by RJR, but Ziegler was not ready to say definitively if that is part of the possible motive.