A statewide grand jury convened in Denver on Friday to investigate missing documents from the Columbine High School investigation.
Ten to 15 Jefferson County deputies including former sheriff John Stone have been subpoenaed. The missing documents include sheriff's field reports of threats made by Eric Harris that led to a 1998 search warrant that was never carried out.
Randy Brown, whose son, Brooks, was the subject of the threats, has said authorities could have prevented the shootings if they had followed up on Harris' threats. Brown says this is a chance for some truth to come out.
The sheriff's and district attorney's office would not comment late Thursday.