Francis Dwyer, 65, was arrested at his residence in Truth or Consequences, N.M., and his son, 38-year-old Odin Leonard Dwyer, was arrested just outside Denver, Colo., according to the sheriff's office.
Mark William Cappello, 46, of Central City, Colo., was arrested Feb. 14 in Mobile, Ala. in connection with the fatal shootings. He is expected to be booked into Sonoma County Jail within the next several days, sheriff's officials said.
The Dwyers are expected to be extradited to Sonoma County in the near future, according to the sheriff's office.
The three men face charges for the Feb. 5 murders of Raleigh Butler, 26, a former Sonoma County resident who was living in Truckee, Richard Lewin, 46, of Huntington, N.Y., and Todd Klarkowski, 42, of Boulder, Colo.
Their bodies were found by Butler's brother and a woman in the bedroom of a cabin Butler's mother rented at 9707 Ross Station Road in the Forestville area.
Sheriff's Lt. Dennis O'Leary said the victims were waiting for someone who was going to sell them "a significant amount of marijuana." O'Leary said, "People associated with the victims said it was a pot deal that went bad."
The sheriff's office recently released photos of two men who are believed to be associates of Cappello and of a Ford Ranger that were taken by a video surveillance camera at a gas station in St. Helena the day before the homicides.
The gold Ford Ranger is registered to Francis Dwyer, and the Dwyers were seen traveling in tandem with Cappello through Wyoming, Nevada and into Napa County days before the homicide, according to the sheriff's office.
Investigators believe all three suspects played a role in the murders of Butler, Lewin and Klarkowski, sheriff's officials said.
"The victims and the suspects were in the drug business," O'Leary said this morning.
The ongoing investigation will include more interviews of people in California and out of state, according to the sheriff's office.