Gavin Eugene Long, who police have identified as the shooter who killed three police officers in Baton Rouge on Sunday (July 17), changed his name in May 2015 and declared himself a part of the Washitaw Nation. Members of the affiliated sovereign group consider themselves independent from the United States and dismiss government authority.

Court documents in Kansas City show Long, who changed his name to Cosmo Ausar Setepenra, claimed his nationality as United Washitaw de Dugdahmoundyah Mu'ur. The Washitaw, sometimes spelled Washitah, believe their ancestors were original inhabitants of the New World, who they say were black Africans.

They trace their lineage back to the ancient Mississippian culture that lived along the river and Gulf Coast. The Washitaw Nation says their claims to the Louisiana Purchase were not recognized when Napoleon sold the large swath of North America to the United States in 1803. The federal government does not recognize their existence, and court rulings have followed suit, NOLA.com reports.

The Washitaw also identify as Mu'urs, which they say is the accurate spelling of Moors, the civilization that developed after the Arab conquest of North Africa. Their movement organized in the mid-1990s in north Louisiana. Their leader, Verdiacee Turner Goston, espoused an Afro-centric take on anthropology and history, said Mark Pitcavage, a researcher with the Anti-Defamation League's Center on Extremism, which tracks the sovereign citizen movement.

Goston, who died two years ago, considered herself the hereditary leader of the Washitaw de Dugdahmoundya, the people responsible for massive earthen mounds across the Gulf South ("Dey Dug Da Mound, Yeah"). Her account of Washitaw history at some point meshed with the teachings of the much older Moorish Science Temple of America, a black nationalist religious movement from the 1920s.

The Washitaw are not the Ouachita tribe of native Americans.

According to a report from the Kansas City Star, Long was involved with the Nation of Islam before joining Washitaw Nation.