Marshalltown Police have taken another man into custody as a material witness in the murder of David Warnell.
Joshua Smith, 23, of Marshalltown, was arrested and taken into custody Sunday as a material witness and also due to a probation violation in Tama County.
Police Chief Mike Tupper said Smith is believed to have information about the homicide.
"Currently they're not looking for anyone else," Tupper said. "It's an ongoing investigation; it can change as things move forward."
Last week police took into custody Bradd A. Quigley, 26, of Marshalltown, Douglas E. Cadotte, 40, of Tama and Alexah M. Mauskemo, 19, of Montour as material witnesses to the homicide.
Quigley, Cadotte and Smith remain at the Marshall County Jail. Mauskemo was released.
Two Marshalltown men are charged in the murder - Jeremy A. Gartin, 30, and Max E. Nelson Jr., 55.
Gartin was charged with first-degree murder and Nelson was charged with accessory after the fact, abuse of a corpse and first-degree theft.
They are both held without bond in the Marshall County Jail.