Investigators believe a fire that damaged a historic trestle bridge near Cold Lake was deliberately set.

The fire at the Beaver River Trestle Bridge, which is part of a trail system that connects a number of communities across northeastern Alberta, occurred on June 22 and caused extensive damage.

The bridge, which spans 450 metres over the Beaver River and is a historic landmark, remains impassable.

Police asy the closure has affected many people who use the Iron Horse Trail including the communities of Cold Lake and Bonnyville and the Municipal District of Bonnyville.

On Thursday, RCMP said the Bonnyville Regional Fire Authority concluded its investigation and said that the cause of the fire was by a person or persons igniting a fire to a vehicle that was located at the base of the bridge.

Police have identified the owner of the vehicle and continues to investigate.

They believe more than one person was involved and say persons of interest have been identified.

Officers believe there were people who were not involved in starting the fire but may have knowledge about how it started. These people are asked to contact Cold Lake RCMP at 780-594-3302 or Crime Stoppers at 1-800-222-TIPS (8477).

The cost of rebuilding the bridge is still being determined.