Four members of a militant group associated with the "boogaloo" movement pleaded guilty to destroying evidence after one of their own told them he had killed a federal officer, the US Attorney's Office announced Monday.

Members of the Grizzly Scouts admitted in their plea agreements to destroying messages in a WhatsApp group and trying to delete files that detailed the militant group's ranks, structure, uniforms, and assessment of members' skills following the killing of a federal officer in Oakland last year. Among the files destroyed was a nondisclosure agreement that prohibited members from talking about the group or its training.