Senior Superintendent Reynaldo Jagmis, Marikina City police chief, said the truck driver tried to counterflow thus occupying the left lane along J.P. Rizal street in Concepcion Uno village around 5:30 a.m.
This caused the jeepney, which carried about 20 passengers, to fall off the gutter as the motorcycle behind him crashed.
Jagmis told INQUIRER.net in a phone interview that the truck driver attempted to crash his truck into a post to avoid collision with the PUJ but to no avail.
The 14 injured victims, meanwhile, were brought to Amang Rodriguez Hospital for treatment.
Killed were the motorcycle driver and three jeepney passengers.
Jagmis said the relatives of the unnamed victims were informed of the accident.
The jeepney and truck drivers are under the custody of the Marikina police Anti-Carnapping division, he said.
Police are still conducting the investigation.