Cocaine found on board the MSC Gayane in Philadelphia Tuesday afternoon

Update: Two crew members arrested and charged. Court documents indicate drugs were loaded onto cargo ship at sea off west coast of South America.

NASSAU, BAHAMAS – United States (U.S.) federal authorities are investigating whether more than 15,500 kilos of cocaine found in seven containers on board a cargo ship in Philadelphia — the largest seizure in the Philadelphia region’s history — was loaded onto the Mediterranean Shipping Company (MSC) Gayane in The Bahamas.

The estimated value of the narcotics is $1 billion.

In a Tweet, the U.S. Attorney’s Office said, “This is the largest drug seizure in the history of the Eastern District of Pennsylvania.”

The cargo ship moored in Philadelphia at 5 a.m. Monday.

Federal agents boarded the ship this afternoon.

It previously stopped in Freeport, Grand Bahama on June 13.

According to NBC 10 News, federal authorities said they were seeking to determine whether the drugs were loaded onto the ship in The Bahamas or while en route to Philadelphia.

When contacted yesterday, Superintendent Jamuel Ferguson, who heads the Drug Enforcement Unit, said he had no information on the drug seizure at this time, and could not confirm whether U.S. authorities had requested the assistance of the Royal Bahamas Police Force.

According to reports, the cargo ship was also stopped in Cristobal, Panama on June 9, the same city on May 24 and Buenaventura, Columbia on May 19.

It scheduled to stop at ports of call in Europe, including France and The Netherlands.

The MSC has 54 cargo ships in its fleet.

Update 8:39 p.m.

In court documents filed Tuesday, it is alleged that two crew members — Ivan Durasevic and Fonofaavae Tiasage — helped to load the cocaine onto MSC Gayane while at sea off the west coast of South America.

The men were charged with conspiracy to possess cocaine aboard a ship subject to U.S. jurisdiction.

According to Associated Press, based on an interview with one of the crew members, a total of 14 boats approached the vessel on two separate occasions.

It remains unclear if additional crew will be charged.