A few nice spy camera images I found:

German Scientist with detective camera (LOC)


Image by The Library of Congress
Bain News Service,, publisher.

German Scientist with detective camera

[between ca. 1910 and ca. 1915]

1 negative : glass ; 5 x 7 in. or smaller.

Notes:
Title from unverified data provided by the Bain News Service on the negatives or caption cards.
Forms part of: George Grantham Bain Collection (Library of Congress).

Format: Glass negatives.

Rights Info: No known restrictions on publication.

Repository: Library of Congress, Prints and Photographs Division, Washington, D.C. 20540 USA, hdl.loc.gov/loc.pnp/pp.print

General information about the Bain Collection is available at hdl.loc.gov/loc.pnp/pp.ggbain

Persistent URL: hdl.loc.gov/loc.pnp/ggbain.10676

Call Number: LC-B2- 2430-14