A 56-year-old homeless man was arrested Tuesday for allegedly setting fire to a Wahiawa auto body shop last week, resulting in nearly $600,000 damage.

The suspect was arrested at Castle Medical Center at 5:30 p.m., where he had been taken for a psychological evaluation Thursday after a witness said they saw him leave the building at the Jetso Auto Center on Palm Street after the fire started.

It took eight fire companies with 34 personnel about a half-hour to to extinguish the main fire, which was first reported about 3:30 p.m.

The fire caused damage of $480,000 to the structure, $100,000 to its contents and an additional $10,000 to vehicles located outside the structure on the same property, according to Honolulu Fire Department spokesman Capt. David Jenkins.

Fire investigators determined that an accelerant was used in setting the fire, Jenkins said.