PNP chief Director-General Ronald dela Rosa, PRO3 director Chief Supt. Aaron Aquino, Zambales PNP officials and Subic Mayor Jay Khonghun boarded the vessel where the four Chinese nationals from Hongkong were arrested.
Reports said three of the four suspects are first timers in the Philippines, with one or two of them possibly chemist of the said laboratory.
A plastic bag containing suspected shabu weighing 1/2 kilo with a street value of P2.5 million was recovered inside the vessel.
The vessel was discovered through the help of fishermen in the area.
Police said the suspects routinely drop their illegal cargo in the sea to be picked up by cohorts who then course their distribution to Ilocos, Cagayan and Pangasinan from Subic Bay.
Intelligence report said this is the second time the vessel was seen docked near Subic Bay, which was first sighted in the area in 2013.
