Check anything with an electic motor that could have been jammed while on. Blender, dishwasher, washer, dryer, any other electric appliance.

Have an electrician come out and check everything. May also consider calling your local fire dept on the non-emergency number to see if they have any suggestions, or if they'll send someone out to check for common issues.

Mice might also be chewing wires. My parents had a minor fire under their dishwasher thanks to that.