Federal agents on Thursday said they had broken up a ring of drug smugglers who used tombstones featuring the Virgin Mary to move hundreds of pounds of cocaine into the United States from Mexico.

The Drug Enforcement Agency announced arrests of 12 people as part of an alleged conspiracy stretching from New York to Mexico City.

Four of those arrests came Thursday, one in Houston and three after an early morning raid on a warehouse in New York's Brooklyn borough.

At the warehouse, agents found bricks of cocaine packed inside tombstones, some decorated with figures of the Virgin Mary, the DEA said.

"Like grave robbers who have no respect for the dead, this drug organization used revered tombstones to smuggle millions of dollars worth of cocaine into New York City," said John Gilbride, the special agent in charge of the New York DEA office.

At the Brooklyn warehouse, agents found eight tombstones, five of which were packed with 20 to 25 kilograms each of cocaine. They also found remnants of smashed tombstones.

An earlier seizure at a Long Island stash house netted 84 kilograms of cocaine and nearly $500,000 in drug proceeds, officials said.

The investigation, dubbed Operation Omni Presence, began in May 2005 based on a tip from Long Island's Nassau County investigators, and it eventually drew in law enforcement personnel in Georgia, Texas, North Carolina and Florida.

The DEA said the raids dismantled the entire supply chain, from the source in Mexico to the New York street dealers. A New York grand jury has indicted the suspects on charges including money laundering, possession with intent to distribute, and conspiracy.

Last month, the DEA said it had arrested a separate group of suspected smugglers who surgically inserted drugs into puppies as part of another scheme.