Detectives of the 50's

A COM 442 Project


Private Eye by AdoC on DeviantArt

This website takes an in-depth look at the work of private investigators and detectives in the 1950’s focusing on the types of communication technologies that they used in their daily business. Here we will talk about what private investigators and detectives did and the different characteristics that defined their professions in the 1950’s. We will take a close look at some of the specific technologies that they used to communicate and aid their investigations. We will also look at the portrayals of private investigators and detectives in the media from this period. We then have a collection of imagery from the period depicting detectives and investigators and the devices they used. Finally, we have a list of resources and links to related materials.

You can use the navigation on the left in order to go through to the different sections.

*Image from

Detectives and Private Investigators of the 50's

The 1950’s was an exciting time in the US for detectives and Investigators. There were many exciting new technologies available to aid in communicating and investigating cases as well as many developments in the field popularly called “police sciences”.

Another exciting movement that took off like a wildfire in the 50’s was fictional representations of the trade in the forms of TV shows, feature length films, radio programs, and written novels. These pieces of popular culture are actually extremely useful in giving us an inside look at how the professions of detectives and investigators were viewed in the time period by the public as well as giving us a look at the actual technologies in action and vivid detail. Through films and TV programs in particular, we can watch actors interact with the technologies the same way an actual professional would in the field.

*Posters from here

What Communication Technologies Did They Use?

This page takes a close look at many of the important communication technologies that private investigators and detectives used on a daily basis in the 1950's. Many of these technologies were just emerging around this time period and many of them (or their predecessors) are still used today in similar ways. These technologies revolutionized the speed and security of communication and the different ways in which detectives and investigators were able to collect evidence and information.


Detective on a Telephone The telephone, of course, was an extremely important tool for detectives and investigators. The telephone served as the main mode of communicating relatively long distances virtually instantaneously. This allowed private eyes to contact partners, informants, secretaries, and anyone else they needed to contact in order to share important information in real time, even from the opposite side of town.

Besides just using the phone in the office to contact other offices and people, detectives and PI's would have used telephone booths when they were out in the field and needed to make quick contact with someone. Something else that telephones could have been used for by detectives, although controversial to this day, was to eavesdrop on conversations through methods of wiretapping. Detectives could listen in on private conversations and even use devices like wire recorders to record conversations to be used as evidence later.[1]

By the late 50's there were developments in speed dialing technologies which would allow the user to just enter one or two numbers and the phone would connect to pre-designated phone numbers.[2] This would be extremely useful to speed up communication for detectives and PI's. They could simply have their most frequent contacts programmed to specific shorten codes so they wouldn't have to look up a number and type in the full thing each time they wanted to make a call.

Wire Recorder

1951 Webster-Chicago Wire Recorder Webster-Chicago 228-1 wire recorder from 1951 (Source)

A wire recorder is a device used for recording analog sound by running a steel wire across a recording head which magnetizes the wire in different intensities based on the sounds being picked up. These techniques of capturing sound were improvements on earlier devices that etched vibrations into disks or cylinders made of thin foils or wax. Wire recorders provided a more durable and flexible media for capturing and storing sounds and made it easier to edit sounds by splicing or re-working sections of the wire. A wire could hold much longer recordings than disks and cylinders and could be re-recorded. The development of wire recorders started in the late 1890's but the technology didn't really take off until decades later in the late 1940's and early 1950's spurred by more economical designs and improvements in the technologies. [3]

In the early 50's wire recorders were starting to be used as tools for wiretapping and gathering evidence to help in court cases. Although wiretapping and eavesdropping were very controversial topics (as they still are today) the wire recorder none the less played a vital role in recording confessions and other evidence that could make or break cases in the courtroom. An article in the University of Florida Law Review titled "Criminal Law: Evidence: Admissibility Of Wire Recorded Confession" describes one of the earliest cases to start a precedence of allowing wire recorded messages as admissible evidence in court.[4] This article states that the court's decision in this case helped to "establish [the wire recorder] as an important device, mechanically sound and legally acceptable, for securing a more successful determination of fact."

These developments in the early 50's paved the way for law enforcement and PI's to be able to use wire recorders as ways of capturing strong evidence of confessions or audio that could be used as clues to other aspects of a case. For instance, an example of a wire recorder for this purpose can be found in a 1952 episode of the TV show "Martin Kane, Private Eye". We will talk more about this episode on the following page, but in this episode, the private eye is able to use a wire recorder to capture the confession of a murder and then present it to the authorities as evidence of the crime.

A wire recorder might also be found in a PI's office for things like recording interviews and interrogations or for easily recording thoughts verbally to be transcribed later. There's no doubt the wire recorder would have been an invaluable tool for detectives and PI's to help capture communication in many circumstances.


1950's Button Camera 1950's Button Camera (Source)

Cameras, of course were very useful for detectives and PI's for capturing evidence or looking for clues. In the 50's there were many developments in sub-miniature cameras, devices that were substantially smaller than the average camera and could capture a picture on much smaller film. These smaller cameras were perfect for things like hidden cameras that a suspect wouldn't even know about. There were cameras disguised as a button of a coat that could be triggered by a lever inside of the pocket of the coat and cameras that could fit inside of a wrist watch.[5]

Wristwatch Camera - Popular Science Steinech A-B-C Wristwatch Camera from 1954 Popular Science (Full Article)

There were many forms of sub-miniature cameras that could be used in all sorts of scenarios. For instance, a PI could be wearing a wristwatch camera like the one pictured on the left, wait for the right time to catch someone in the act of something incriminating and just subtly pretend to check the time while actually taking a photograph of the scene. Sub-miniatures came in more traditional forms as well which would were more portable and handy that a full size camera. A detective might keep a small cigarette pack-sized camera on them at all times just in case it would come in handy. They could be used for taking photos of a crime scene or an important clue.

Another development in photography in this period was the use of infra-red cameras. Detectives were able to use infra-red cameras to take photos in dark places where visible light was low. These cameras could use an infra-red flash which wouldn't be detected by the human eye, but would work similarly to a regular flash.[6] These cameras could be set up to take photos similar to how a security camera or hidden camera might be used today. If a detective hears that an illegal deal or incriminating act might go down at a certain location, they could then set up an infra-red camera with a timer beforehand and hope to capture photographic evidence.

Answering Machine

1953 Peatrophone - Popular Science Peatrophone in 1953 Popular Science (Full Article)

By the 1950's the answering machine had been around for more than half a century, but it wasn't until the 50's that they actually started becoming commercially available and used by the public. The first answering machines to be used domestically and for small businesses were called Peatrophones and were rented out by telephone companies for around $12.50 in the early 50's. These machines used the same methods of recording and playing sound that were used by phonograph record players. There were essentially two turntables, each of which played its own recording disk, a small one for an outgoing message and a larger one for incoming messages. When the machine was activated, if a call came in on the phone line, the machine would connect to the phone line, play the pre-recorder outgoing message, and then start recording the incoming message to be played back later.[7]

For detectives and PI's this device could be used in the office while they are out and about conducting investigations to make sure that calls were all answered. If a PI didn't have a secretary, this would particularly useful. This machine meant that if a potential client called in while the PI was out of the office, instead of getting no answer and moving on to the next listing in the phonebook, they would be prompted to leave a message and the PI could get back to them and secure the new client.

Some other interpreted uses might have arisen out of these devices as well that could prove particularly helpful for detectives and PIs. One thing these machines could be used for why the PI wasn't out is an idea we are all too familiar with today, call screening. The PI could intentionally let the phone ring and have the answering pick up so they could tell who was calling without giving away that they were in fact in the office. We'll look at an example of an answering machine being used by a PI for just this in the next section when we look at the film "Kiss Me Deadly".

Another unintended use of answering machines that could have been very helpful to PI's is to use it as a personal memo device when they are out of the office. If there's some important thing that they need to remember and get a reminder of, they could call into their own office and leave a recording on their own machine. Then when they return to the office, they will see that there are new messages and be reminded of the memo they sent themselves.

Detectives and Private Eyes in 50's Pop Culture

Throughout the 1950's, there was a rich theme of detective and private eye TV shows, movies, and novels. The Film Noir movement, in particular, brought with it many stories of detectives and investigators to the big screen. These different pieces of media can give us an interesting insight into how detectives and private eyes would use the technologies of the time to help them solve cases and make their jobs easier. Douglas Snauffer starts his book Crime Television by stating that "in many ways, crime dramas, whether they've focused on uniformed police officers or private investigators, have more closely mirrored actual society than any other genre".[8] I have taken several examples of these media and examined them for pieces of communication technology that aided the main characters in their cases.

Martin Kane, Private Eye (1949 - 1954)

This long-running television show from the early 50's follows the suave and cleaver private eye, Martin Kane. As the hero of the show, Kane does investigates a new case in each episode and performs many typical investigative tasks finally leading to a shocking conclusion of who or what had caused the mystery. During his investigations, Kane uses many different tools and technologies to get to the bottom on the matter at hand.

Wire recorder used in 'Martin Kane, Private Eye' Webster-Chicago wire recorder used by Martin Kane

In one episode I watched titled "Night Club Murder", which aired in 1952, follows the mystery of a murder that took place in a night club. Throughout the episode, Kane interrogates all of the people who were present during the murder. A few obvious choices for the murderer are presented to allow the audience to play along and work on solving the mystery themselves, but in the end, Kane is able to pick up clues that lead him to a character that no one would expect. After getting the suspect in quiet room, he talks her into confessing her crime.

Luckily, Kane had placed a wire recorder in the room beforehand and set it to record the conversation in order to have proof on the confession. After capturing the confession on the hidden device, Kane exclaims, "this is my little witness, a wire recorder, and the duet that you two just sang will really be music to some judge's ears." He is able to hand over the recording to the police and bring the murderer to justice. Although this was a purely fictitious story, it paints a clear example of how a detective or PI could use a recording device and present it as admissible evidence in a courtroom.

This episode can be viewed in full here. He wire recorder can be seen in action at 22:50.

On a side note, this episode of this early 50's TV show give us an interesting perspective of how television was drastically different than what we are all used to today. Advertising is very integrated with the actual production of the show from the introduction to the scenes with close-ups of packs of tobacco zooming out to the main character smoking his pipe with a smile on his face. There's hardly a character in the whole show who isn't smoking something.

Kiss Me Deadly (1955)

This 1955 Film Noir mystery features hardboiled private eye Mike Hammer who gets thrown, by matter of circumstance and curiosity, into an intense and dangerous case involving car wrecks, explosions, kidnappings, seduction, and cold-blooded murder. Now we couldn't exactly expect this to be the typical kind of case a private eye or detective would actually find themselves in the middle of in the 50's, but through its over-dramatizations and fantastical scenarios, we can still get an intimate look at many of the technologies that really would be used by the detectives and PI's of the time. Throughout the course of this dramatic, fast-paced mystery, we can see all kinds of technologies being used such as cameras, TVs, telephones, early answering machines, radios, record players, type writers, and even plain old postal services.

Answering Machine in 'Kiss Me Deadly' Mike Hammond screening a call with his answering machine

Around 18 minutes into the film, we are first introduced to Mike Hammond's home and headquarters in a sweeping shot of the apartment. We first see several cameras hanging by his door and a television set in the living room. Then, we hear a telephone ring followed by a recorded voice playing a message. The camera pans over to Hammer's desk with a telephone and a wall-mounted answering machine. An answering machine could be extremely useful to a PI given that they are out and about for a good chunk of their day. Answering machines would be helpful for taking phone messages while out of the office, but the way Mike Hammer uses his machine is quite interesting. Instead of answering the phone the first few times it rings, he intentionally lets the answering machine pick up the call so that he can find out who is calling without them knowing that he is there. After hearing his assistant's voice, he is able to pick up the phone and talk with her. He essentially uses his answering machine very similarly to how modern answering machines and caller ID are used today to screen calls. The answering machine was already being interpreted for unintended uses, even in the early days of its development and it proves particularly useful for Hammer given his profession.

Throughout the film, Hammer uses telephones to reach people quickly that he wouldn't be able to contact as immediately otherwise. Even when he's out of the office and on the streets, he uses payphones in order to relay urgent messages. In a particular scene towards the end of the film, Hammer is actually able to use a phone to gather information without any verbal communication. He calls the front desk of a club that he had just visited and after the phone rings a half a dozen times, he gets the message that the man running the desk had been killed. The lack of communication over the phone was actually able to be used to gather information.

The film can be watched online in its entirety here.