FBI agents investigating hypothermia death on Fort Belknap

The FBI, in conjunction with the Fort Belknap Police Department, is investigating the death of 48-year-old Antonio Castillo Jr., who was found dead of hypothermia Dec. 29 on the reservation.

“We are investigating Mr. Castillo’s death along with the Fort Belknap Police Department and an assist by the Blaine County Coroner,” Travis Burrows, supervisory senior resident agent with FBI Billings, said in an email Wednesday.

Blaine County Undersheriff Frank Billmayer said in an email Thursday that Castillo died of hypothermia and exposure in an “aged bumper pull type camper trailer with an insufficient heat source for the sub-zero ambient temperatures” two days before the new year.

The cause of death, Billmayer continued, has been determined to be “accidental.”

Billmayer said he could not comment on the incident the FBI may or may not be investigating or on further questions about Castillo’s death.

“The Blaine County Sheriff Coroner’s Office has received no allegations, statements or observed any evidence to support any other cause and manner of death than that which is stated above,” Billmayer said.

Late Thursday afternoon, Burrows said the FBI had no further comment about the investigation of Castillo’s death beyond that given Wednesday.

Fort Belknap police did not comment and criminal investigator Curtis Fox did not return calls for information requests on Castillo’s death.