06/21/2015 05:42 EDT | Updated 06/21/2016 05:59 EDT

Serious crash closes Pattullo Bridge, sends 4 to hospital

A major crash on the Pattullo Bridge sent four people to hospital Saturday night, and closed the 78-year-old bridge in both directions for several hours.

An investigator with the RCMP Integrated Collision Analysis and Reconstruction Service said a northbound tow truck may have crossed into oncoming traffic, causing the four-vehicle crash, just after 8 p.m. on the Surrey, B.C., side of the bridge.

The B.C. Ambulance Service said one person was taken to hospital in serious condition. Three others were transported in stable condition.