Police have arrested five people after several bodies were found shot dead in a remote area of southern California's Mojave Desert.
Six bodies were found after a gunshot victim called 911, sending a police helicopter to the grisly crime scene.
Investigators for the San Bernardino Sherriff's Office said on Monday that the dispute appears to be related to illicit marijuana production.
Four of the six victims have been identified so far, police said.
The bodies - all men - were found on 23 January off a highway near the town of El Mirage, located in San Bernardino County. All six victims died from gunshot wounds, police said.
Four of the victims had also sustained severe burns, Sgt Michael Warrick told reporters on Monday.
The investigation began when 911 emergency operators received a call from one of the victims reporting that he had sustained a gunshot wound.
A police helicopter was launched and located the victims, as well as a bullet-riddled SUV and minivan at about 20:15 local time (04:15 GMT), about 90mi (144km) northeast of Los Angeles.
Four of the men were found near each other, while another was located in a vehicle. Officers discovered the final body a short distance away.
Aerial footage of the scene appeared to show the SUV riddled with bullets and marked by shattered windows and the remnants of a fire.
"As far as the motive, we are confident that this appears to be a dispute over marijuana," said Sgt Warrick.
In a news release, the sheriff's office said the that "investigators determined the victims had arranged to meet at the location for a marijuana transaction".
The five men who have been arrested "arrived at the location, and for reasons still under investigation, shot the six victims".
Eight guns have been confiscated by investigators and are being tested to determine if they were used in the killings.
Officials refused to comment on whether the killings were cartel or gang-related, instead attributing them to "organised crime".
Cannabis has been legal for adults to purchase and use in California since 2016, but a black market remains for untaxed marijuana.
Last year, police in San Bernardino County executed 411 search warrants for illegal marijuana operations, and seized 74,000lbs (34,000kg) of processed cannabis, according to the sheriff's office.
