SLEX patrol supervisor Manolito Altarez identified the fatalities as Romeo Nueva, 42, a certain Roberto Mendoza, and Philips Electronics employees Myrna Castel and Elizabeth de Claro, who both died while undergoing treatment at various hospitals.
Nueva was the driver of Melissa Passenger bus (DWJ442), plying the Calamba-Alabang route.
Among the injured who were said to be in critical condition at the Asian Hospital in Muntinlupa City were Anabelle Sarinas and Nilda Banagua.
The unidentified driver of the Gold Trans Shuttle Bus (NYJ 360), which slammed into the passenger bus, escaped after the incident, said Manny Frades of the Philippine National Construction Corp. (PNCC), which manages and operates the SLEX.
The shuttle bus was reportedly rented by Phillips Electronics which has its factory in Cabuyao, Laguna.
Another shuttle bus (TWF) 390) and an Isuzu Elf truck carrying pig carcasses, both southbound, were also damaged in the accident.
Frades said the incident happened at around 5:34 am in Barangay Suro-Suro, Biñan, just after the bridge near the Carmona Interchange.
Frades said that the passenger bus was on the northbound lane and the shuttle bus on the southbound lane.
But the latter suddenly swerved to the northbound lane and collided with the other vehicle.
The strong impact shattered the drivers side of the passenger bus and pinned Nueva to his seat, Frades said, adding that it took rescuers nearly an hour before they could extricate him.
Nueva was killed on the spot.
The injured passengers were rushed to different hospitals for treatment. With Ed Amoroso.