A Florida county sheriff's office says they arrested a former law enforcement officer whom federal authorities say planned a mass shooting targeting Black people at a large festival in New Orleans. The event wasn't named, but the annual New Orleans Jazz & Heritage festival got underway Thursday. The Okaloosa County Sheriff's Office says Christopher Gillum from Chapel Hill, North Carolina, was wanted for terroristic threats. Deputies arrested him Wednesday at a hotel and found a handgun and about 200 rounds of ammunition in his room. Gillum once worked in a North Carolina county sheriff's office and as a police officer. It wasn't known if he had a lawyer and phone messages were left for him.