28 CFR §551.101

1. (a)Pretrial inmate. For purpose of this rule, “pretrial inmate” means a person who is legally detained but for whom the Bureau of Prisons has not received notification of conviction. Thus, “pretrial inmate” ordinarily includes a person awaiting trial, being tried, or awaiting a verdict.
   1. (1)Civil contempt, deportable aliens, or material witnesses. For purpose of this rule, an inmate committed for civil contempt, or as a deportable alien, or as a material witness is considered a pretrial inmate.
   2. (2)Mental evaluation or treatment. An inmate committed under Title 18 U.S.C. Sections 4241 (b) and (d), 4242(a), or 4243(b) is considered to be a pretrial inmate, whereas commitments under Sections 4243(e), 4244, 4245 or 4246 are treated as convicted inmates.
   3. (3)Concurrent federal and state sentences. For purpose of this rule, an inmate in a status described in paragraph (a) introductory text, (a)(1), or (a)(2) of this section and who is at the same time serving a state or federal sentence is not considered a pretrial inmate.
2. (b)Convicted inmate. For purposes of this rule, an individual a court has found guilty of an offense punishable by law.