| 2024-02-11 | P.I.s, e.g. |
| 2023-07-16 | Gumshoes |
| 2021-08-23 | Sleuths, in old slang |
| 2021-06-16 | Gumshoes |
| 2020-11-15 | They're on the case, in slang |
| 2019-10-06 | Clue collectors, for short |
| 2019-02-16 | People on the case, for short |
| 2018-05-04 | Private eyes |
| 2016-11-08 | Private eyes, in slang |
| 2014-11-17 | Gumshoes, in old crime fiction |
| 2014-08-23 | Slag for sleuths |
| 2013-11-20 | P.I.'s |
| 2013-09-27 | Many pulp heroes, in slang |
| 2012-06-30 | Hammer or Spade types |
| 2010-02-08 | Private eyes, for short |
| 2007-08-26 | Shadows |
| 2007-03-24 | Shadows, briefly |
| 2007-03-06 | Private eyes, for short |
| 2006-02-19 | P.I.'s |
| 2005-12-04 | P.I.'s |
| 2005-02-14 | Private investigators, for short |
| 2004-08-10 | Private eyes |
| 2002-11-06 | Gumshoes |
| 2001-05-08 | Hired sleuths, slangily |
| 2000-10-03 | Private eyes, slangily |
| 2000-06-15 | Sleuths, for short |
| 1999-12-25 | Clue hunters, slangily |
| 1997-11-16 | P.I.'s |
| 1997-09-18 | Lt. Columbo et al. |
| 1997-08-24 | Gumshoes |
| 1996-03-16 | Clue finders |
| 1994-12-26 | Private eyes, in slang |
| 1994-06-01 | Gumshoes |