Fire officials in Peoria estimate flames at the abandoned historic downtown Madison Theater caused $500,000 in damage.
The Peoria Fire Department says the investigation continues into the cause of the Saturday night fire that was sparked in the backstage area before spreading. The fire department says the building remains structurally sound.
The theater was listed on the National Register of Historic Places in 1980. In 2013 Landmarks Illinois listed it as one of the state's most endangered historic places. It was closed in 2003 when city inspectors determined it needed safety upgrades.
Bill Ordaz, president of the Central Illinois Landmarks Foundation, says the theater is "a critical part of Peoria" that "still has potential."
Several redevelopment proposals have been discussed, though no action has been taken.