US coast guards have recovered more than four tonnes of marijuana - 160 bales - floating off the coast of California, in a mystery incident, police said Monday.
The drug haul, worth more than $3 million on the street, was spotted Sunday off the coast of Dana Point, some 96 km (60 miles) south of Los Angeles, said local sheriff's office spokesman Joe Balicki.
A drug smuggling accident would be an obvious explanation, though the amount involved would have required a larger vessel than a small craft typically used to smuggle drugs around the nearby Mexican-US border.
"It kind of makes you wonder how it got there," Balicki said, adding: "We didn't have any reports of vessels in distress." The bales, wrapped in plastic, were found bobbing in the sea about 15 miles (24 km) from shore.
The drugs were picked up by the US Border Patrol agents assisted by the US Coast Guard and Orange County Sheriff's Department Harbor Patrol deputies, he added.
Border Patrol official Michael Jimenez, told the Orange County Register that large drug shipments are sometimes dropped overboard when smugglers have to flee from authorities.
"At other events, they've dumped the bales to get rid of weight if they're being chased," he said. "Generally in these cases we're aware they're being dumped.
"What's more unusual is that the bales were floating with no boat in sight."