Officials with the South Dakota Department of Public Safety say two people are dead after the garbage truck they were driving ended up in the James River northeast of Letcher.
DPS Public Information Officer Tony Mangan says the case began on Thursday.
He says that's when the Sanborn County Sheriff's Office received a report of a guardrail being hit on Highway 37.
"And then on Friday, the two occupants of the garbage truck that had not come home - their families had contacted the Sheriff's Office and reported them missing. So, the search began in that area by the James River bridge on Highway 37 on Saturday. They found the truck sometime Saturday, the rescue people did, in the water. And, then they were able to recover the bodies when they found the vehicle on Sunday."
Mangan says authorities have inspected the garbage truck.
"And, initial thought is that there was some sort of mechanical failure that occurred that caused the vehicle to go off the roadway at the beginning of the crash. So that'll be something that Highway Patrol investigators look at as they continue their investigation."
A statement from the Department of Public Safety notes several state and local agencies assisted in the search and recovery efforts.
Authorities have not yet announced the names of the deceased.
Officials ask the public to stay away from the recovery area.