A fire at a vacant house in Barrie is being treated as an arson investigation.

The vacant home on Essa Road went up in flames just before 4 p.m. Saturday.

The blaze was deemed suspicious and the Ontario Fire Marshal’s Office (OFM) was notified. OFM investigators spent Sunday on the scene.

Police say witnesses saw four young people running from the house when the fire broke out.

Investigators have obtained evidence from the home which is believed to be a contributing factor to the fire.

Anyone with information is asked to contact police.