Four men were shot and dismembered before their bodies were thrown into a river in Oklahoma, U.S. police said.
A man believed to be involved in the case has since disappeared.
Investigators found the first bodies of victims Friday after a passerby saw suspicious objects in the Deep Fork River near a bridge, Okmulgee Police Chief Joe Prentis said. He added that their bikes had not been found.
“All four bodies were dismembered before being placed in the river, which is why it was difficult to identify them,” Mr Prentice said.
“The river appears to be a dump. Now this is a murder investigation.”
The victims have been identified as Mark Chastain, 32, Billy Chastain, 30, Mike Parks, 32, and Alex Stevens, 29.
They were reported missing on October 9 after cycling away from Billy Chastain’s home in Okmulgee around 8pm.
Mr Prentice said investigators believed the men intended to “commit some sort of criminal act” that night.
Mr Prentice said Joe Kennedy, the owner of a vandalism site, was believed to be a stakeholder in the case after “evidence of violence” was found at a nearby property.
A ping from Mark Chastain’s cell phone brought police to the area.
Mr Kennedy has not been named as a suspect in the case, but the police chief said he was missing and asked the public to report any sightings of him.