A fire on Main Street in Boonville that left 29 people homeless has been ruled arson.

Boonville Police say 34-year old David Geer, who lived in the apartment building, intentionally set fire to his mattress with a cigarette.

Police say Geer allegedly removed valuable items from his apartment and also prevented neighbors from entering the apartment to try and put out the fire.

Geer was charged with second-degree arson.