DIs are required to testify as to the results of their investigations during criminal trials , grand jury proceedings and administrative hearings .
DIs also work closely with attorneys for DEA , the United States Attorneys Office and state and local prosecutors .
DIs are required to testify as to the results of DEA 's investigations during criminal trials , grand jury proceedings and administrative hearings .
DIs also work closely with attorneys for DEA , the United States Attorneys Office and state and local prosecutors .