At least some of the seven people arrested in a fatal shootout with Louisiana deputies have been linked to violent anarchists on the FBI’s domestic terrorism watch lists. Detectives had been monitoring the group before Thursday’s shootout in Laplace, La., in which two deputies were killed and two more wounded, DeSoto Parish Sheriff Rodney Arbuckle said Saturday. His detectives and other law enforcement discovered the suspects were heavily armed adherents to an ideology known as the ‘‘sovereign citizens’’ movement.