MANILA (UPDATED) - Authorities on Wednesday filed charges against four persons in connection with the P2.4-billion worth of shabu found at the Manila International Container Terminal (MICT) on August 7.

Charges of conspiracy in the importation of illegal drugs and possession of dangerous drugs were filed against Chan Yee Wah Albert, Zhang Quan, Vedastro Baraquel Jr., and Maria Lagrimas Catipan before the Department of Justice (DOJ).

The Philippine Drug Enforcement Agency (PDEA) initially said the drugs weighed 500 kilos with an estimated value of P4.8 billion. It was later determined that the contraband weighed 355 kilos.

• P4.3 bilyong halaga ng shabu, nasamsam sa Manila port

The shipment was loaded inside a 20-foot shipping container reportedly misdeclared as door frames that arrived on June 28 from Malaysia and declared abandoned 30 days later after no one came forward to claim the cargo.

A day later, four more magnetic lifters were found in Cavite but they were empty.

The PDEA said they were on the hunt for at least 5 more containers with a ton of shabu worth at least P6.8 billion.

• Nasa P7 bilyong halaga ng shabu, naipuslit sa Pilipinas?

The agency later said it only had circumstantial evidence in claiming that illegal drugs slipped past the Bureau of Customs through the empty containers.

• PDEA: 1-ton shabu proof 'only circumstantial'

Authorities said loading illegal drugs into magnetic lifters will render the drugs unnoticeable through x-ray machines and difficult for drug-sniffing dogs to distinguish. - With a report from Ina Reformina, ABS-CBN News

• BOC official: Customs x-rays couldn't have detected shabu in magnetic lifters