Investigators are calling an early morning fire that destroyed a playground at a Chico elementary school suspicious. Firefighters were called out to Hooker Oak Elementary School on Arbutus Avenue just after 3 a.m. Friday morning for a report of a rubbish fire. The blaze started on a playground, destroying most of the structures. No estimate has been given for damages, but school officials say the playground cost around $50,000 to build. Fire officials say the blaze does seem suspicious, but are still trying to determine a cause.