The Work of Postal Inspectors: Exploring the Call of the Silent Service

I became fascinated with the United States Postal Inspection Service when, as an intern for the National Law Enforcement Museum, I researched a criminal case for the Web of Law Enforcement exhibit (check it out on your next visit). That was five years ago, and since then, I have learned a lot more about this impressive law enforcement organization. Postal Inspectors, sometimes called the “Silent Service,” have made major impacts on American law enforcement procedures and in important criminal investigations.


National Law Enforcement Museum’s Web of Law Enforcement exhibit

The Postal Inspection Service traces its roots to 1772 when Benjamin Franklin, Founding Father of the United States, was appointed as the first American Postmaster General by the Second Continental Congress. In a letter dated August 7, 1775, he appointed William Goddard as the first American Postal Surveyor whose duties included “inspecting the integrity and security of postal routes, regulating post offices, and auditing their accounts.”[1] Today, Postal Inspectors have focused solely on the first of Goddard’s duties, investigating crimes that affect or fraudulently use the US Mail, postal system or postal employees.
The mail service is an integral part of our country. Sending someone a letter was the only way of communicating with faraway relatives or business contacts for hundreds of years. Victoria Bruce, co-author of a new book on US Postal Inspector Frank Oldfield, explained, “a post office inspector was stationed in key transportation and logistics hubs in the United States to protect the flow of commerce and money.”[2] While the internet has made communicating with people so much easier, we still rely on the mail service to deliver packages, send money, and receive vital information.
Criminal organizations also understood the importance and advantages of the mail service. In the early 1900s, the Black Hand, an extortion ring, used the mail to deliver threatening letters, terrorizing Italian and Sicilian immigrants. Postal Inspector Oldfield’s investigation into the Black Hand in Ohio led to the first national organized crime conviction for the US. Postal Inspectors. Other major cities like New York and Chicago were also dealing with threats from the Black Hand.

2006.280.1.31 Glass negative from an NYC murder investigation related to the Black Hand

The transportation of mail was a prime target for criminals. Mail stagecoaches, trains, and carts have been under attack since the founding of the postal inspection service. In 1936, Alvin Karpis, who was declared “Public Enemy #1”, was apprehended by Postal Inspectors and Kansas State Police. Karpis and four other men had stolen $34,000 in currency and $11,650 in bonds from a mail train in a “spectacular machine-gun holdup” in Garrettsville, Ohio.[3] Postal Inspectors were the first federal agency to utilize the Thompson Submachine-Gun, known as the “Tommy gun,” because of the violence around mail robberies in the 1920s.
Postal Inspectors have been on the cutting edge of law enforcement technologies. William Oldfield, the inspector’s great-grandson, wrote, “[Inspector Oldfield] utilized new techniques that were still in their infancy world-wide, such as handwriting analysis, stakeouts, using the newspapers to call out or intimidate criminal as well as human intelligence.”[4] Postal inspectors used forensic science for many of their major cases. Stephanie Smith, assistant lab director of the Physical Sciences Unit at the National Forensics Laboratory in Washington, DC, said, “past and present scientific staff…worked closely with the Postal Inspection Service on high-profile cases including the Unabomber case; the Chugiak, Alaska, mail bomb case; the conviction of televangelist Jim Bakker on mail fraud.”[5] The first postal inspection service forensic laboratory was opened in 1940 and Smith now works in its updated facility. There are four additional labs in New York, Chicago, Memphis, and San Francisco to analyze evidence and aid investigations.

2007.110.1 UNABOM reward poster

One of the major cases mentioned by Smith was the Unabomber investigation, the longest open serial bomber case in American history. Ted Kaczynski used the mail service to deliver nine of his 16 devices between 1978 to 1996.[6] Postal Inspectors worked with Federal Bureau of Investigations (FBI) and Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) special agents as members of the UNABOM Task Force. After many years without a break in the case, Kaczynski sent a manifesto to newspapers demanding that it be published. Kaczynski’s brother identified Ted’s writing from the newspaper and notified authorities. UNABOM Task Force arrested Kaczynski in 1996, near his cabin in remote Montana.
Postal Inspectors have also been combatting fraud since their inception. Notable cases occurred during the Civil War when mail order cure-alls were popular and in the 1920s when inspectors investigated Charles Ponzi, the father of illegal pyramid schemes. As most of our communication and business transactions have moved to the internet, the postal inspector’s work has also evolved to include electronic crimes. According to A Law Enforcement Guide to the U.S. Postal Inspection Service, “[Electronic crimes] includes using or selling stolen or counterfeit access devices, such as credit card numbers; using protected computers without proper authority…using computer communications in a scheme to defraud; and unauthorized access to communications that are stored electronically.”[7] Many of these crimes are an extension of the Postal Inspector’s mission to protect customers from fraud schemes that misuse the mail or Postal Service.
As one of our longest-serving federal agencies, the US Postal Inspection Service has evolved along with our country to better combat crime and keep citizens safe. Inspectors have the honor of many firsts in American law enforcement – the first use of the Tommy gun, first to use the title “special agent,” and one of the first to admit women as officers. It is important to remember the significant and lifesaving work Postal Inspectors do every day.


Alyssa Foley is the Manager of Adult and Family Programs at the National Law Enforcement Museum. Alyssa’s favorite object in the National Law Enforcement Museum’s collection is a picture of J. Edgar Hoover and Shirley Temple enjoying a leisurely day outside.
[1] “History,” United States Postal Inspection Service, accessed August 29, 2019,
[2] Seth Feranti, “How a Postal Inspector Brought the Mafia to Justice,” Vice, August 24, 2018,
[3] United States Postal Inspection Service: Because the Mail Matters (U.S. Postal Service, Publication 162), 10-11,
[4] Seth Feranti, “How a Postal Inspector Brought the Mafia to Justice,” Vice, August 24, 2018,
[5] Sara Goudarzi, “Perspectives On: A Forensic Lab,” Lab Manager, January 20,m 2012,
[6] “Unabomber,” Smithsonian National Postal Museum,
[7] A Law Enforcement Guide to the U.S. Postal Inspection Service (U.S. Postal Service, Publication 146, September 2006), 9,