MANILA, Philippines -- Major Ferdinand Marcelino, head of the Philippine Drug Enforcement Agency's (PDEA) Special Enforcement Service, was unable to attend the investigation at the House of Representatives Tuesday because of a buy-bust operation, PDEA spokesman Derrick Carreon said.

In a phone interview, Carreon said Marcelino headed the drug bust in the city of San Juan Tuesday morning where the suspect, identified as a Filipino-Chinese businessman, was arrested.

Carreon said he was uncertain if Marcelino would be able to attend the House investigation.

Marcelino also led the buy-bust operation against Richard Brodett, Joseph Tecson, and Jorge Joseph whose case is now the subject of an investigation at the House of Representatives following allegations of a bribery attempt at the Department of Justice and the PDEA.