The lawmen were gunned down along Interstate 95 in Cumberland County last September after a traffic stop.
Judge Coy Brewer also ruled that statements the brothers to police will be allowed as evidence. Jury selection for the case begins next week. The trial will be held in Cumberland County, but jurors will be selected from Johnston County because of pretrial publicity about the case.
The prosecution has already told the judge it will seek the death penalty against the brothers if they are convicted.