A police report said the ambulance was travelling on the national highway in Sitio Guisokan towards Dipolog City when it collided with an Isuzu hauler truck travelling in the opposite direction.
Investigation showed that the truck veered towards the lane occupied by the ambulance after the driver lost control of the steering wheel during a brake malfunction.
Ambulance driver Joseph Lopena and truck driver Mario Macatual were killed on the spot.
Four passengers of the ambulance were declared dead on arrival in a Sindangan hospital: Analisa Maribojoc, Princess Gold Ejan Sangilan, Julie Jay Sumonglay, and a still unidentified person.
Five others in the ambulance were injured. They were Saturnino Nelles Tagulod, Sany Boy Rubayan, Izan Encion Luz, Flora Mae Toto Antoc, and an identified passenger.