U.S. prosecutors say more time is needed to work through the voluminous evidence in the complex case against an alleged white supremacist group member and former Manitoba reservist Patrik Mathews.

A former army reservistand two other alleged members of a violent neo-Nazi group discussed"executing"a police officer to steal his weapons and "committing targeted acts of violence" at Monday's pro-gun rally in Virginia, according to documents filed Tuesday in a Maryland court.

FBI officers have arrested more alleged members of a racially motivated and violent extremist group that a former Manitoba reservist has been accused of recruiting for and court documents tell a chilling tale that includes plans to murder a married couple and overthrow the U.S. government.