A man was arrested Sunday evening after breaking into his ex-girlfriend’s home in Sunrise and setting it on fire, doing over $100,000 in damage, police say. He was carrying a loaded gun with one round in the chamber. Keith Derick Mitchell, 36, of Fort Lauderdale, is now facing charges of armed burglary, second-degree arson, committing a third degree felony with a firearm, criminal mischief, possession of a firearm by a convicted felon, resisting an officer without violence, and tampering with physical evidence, jail records show. Sunrise Police responded to the home in the 5400 block of Northwest 92nd Avenue in reference to a burglary in progress Sunday afternoon, according to a probable cause affidavit.