Powell National Detective Agency Yellow Page Ad, Denver Colorado, 1931
Note the fact that Powell National Detective Agency offered what was called Dictograph Services.Click on the blue link to learn all about what the Detective Dictograph was. Since Dictograph services is listed first and in all caps, you can assume this was a big thing for the agency. The Dictograph at the time was a modern, new age, high tech audio listening device that was the marvel of it's time. The agency was founded, according to the ad; in 1910. In 1931, they had thus been in business for 21 years. Mr. Powell was likely very well established. Note the wordage "Frequently Using Camera" and "Conducted Without Publicity". It's interesting to note that Powell National Detective Agency listed "employee investigations for firms and corporations" at this time period. In this era, surveillance was called shadowing. Note that this ad listed a main number and then three separate telephone numbers below for after hours calls. William Powell's home address is listed in the 1931 Denver phone book as (and we quote)

Powell, William, r
W 12th And Wadsworth Av TAbor 6975

Since four phone numbers were listed, you can assume that this agency did NOT want to miss any phone calls. Remember, there was no such thing as call forwarding nor answering machines for this time period. It's interesting to note that the agency listed Blackmail, Kidnappings and murder as investigative services. Although there were some international and national associations of this time period, we are not sure what "associates in major cities" means. However, investigative services like this had competition like Pinkerton's National Detective Agency that had offices in every major city.

From The Ralph D. Thomas PI Vintage Collection
THOMAS INVESTIGATIE PUBLICATIONS, INC.
NATIONAL ASSOCIATION OF INVESTIGATIVE SPECIALISTS, INC.
SPY EXCHANGE AND SECURITY CENTER
P O Box 82148, Austin, Texas 78708
Showroom: 9513 Burnet Road, Austin, Texas 78758
Phone 512.719.3595 Fax 512.719.3594
Email: RThomas007@aol.com

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