Historical clue formulations

• Workplaces for dets. — 2020-01-10
• They have sgts. — 2017-09-09
• Groups in blue, for short — 2015-11-21
• A.P.B. issuers — 2015-04-24
• Groups of cops: Abbr. — 2014-09-02
• They have precincts: Abbr. — 2009-07-27
• A.P.B. broadcasters — 2005-12-04
• Law enforcement hqrs. — 2004-09-05
• Places for sgts. — 2003-01-17