Scope and Content Note
The records of Pinkerton's National Detective Agency, oldest company of private investigators in the United States, span the years 1853-1999 with the bulk of the material dating from 1880 to 1920. The collection documents the history of the agency founded circa 1850 in Chicago by Scottish immigrant Allan Pinkerton (1819-1884), a leading figure in crime detection, particularly for clients in business and industry. It consists of main office files from New York and Chicago and is organized in five series: Family Directors File, Administrative File, Criminal Case File, 2020 Addition, and Oversize. Branch offices files are not generally included. Furthermore, many family and business papers burned when the agency headquarters was destroyed in the Chicago fire of 1871.
The Family Directors File includes material from all five of the Pinkerton men who ran the agency from 1850 to 1967. Records for founder Allan Pinkerton include newspaper and magazine articles about him, and a book manuscript, but only a few original primary documents. Scattered correspondence, photographs, and mementos, such as railroad passes and a phrenological analysis of Pinkerton's character and future prospects, are available in the series. Records concerning Pinkerton's death in 1884, his funeral and memorial tributes, are more extensive.
Pinkerton's sons, William (1846-1923) in Chicago and Robert (1848-1907) in New York, expanded the agency during the last quarter of the nineteenth century. It is primarily the criminal division of their business that is documented in this collection. At the time of Robert Pinkerton's death in 1907, the agency had two thousand employees, safeguarded four thousand banks in the United States, and had branch offices operating throughout the country. Correspondence between William and Robert in the Family Directors File complements the Criminal Case File since much of it concerns criminal investigations undertaken by the agency.
Robert's son, Allan Pinkerton (1876-1930), managed the New York office after his father's sudden death in 1907, continuing the agency partnership with his uncle, William, who remained head of the Chicago office. His files include records of military service during World War I and items reflecting the agency's involvement in homeland security. When William died in 1923, Allan Pinkerton incorporated the agency and became sole family director. Incorporation records are included in his segment of the Family Directors File. Allan's son, Robert Pinkerton (1904-1967), succeeded him in 1930 and was the last of the family to direct the agency.
The Administrative File selectively documents business principles and practices. Policy statements, procedural guidelines, and training manuals provide an outline of the agency's approach to soliciting business and conducting private investigations to protect the interests of individual clients. Agency policy also called for cooperation with law enforcement officials requiring that evidence be given to police and prosecuting authorities when a case reached the point of arrest and prosecution. There was no federal police agency in the nineteenth century, and the Pinkerton agency played a prominent role in apprehending lawbreakers, particularly train and bank robbers and jewel thieves. As bankers and jewelers formed associations for mutual protection, Pinkerton's provided security services to these associations. The agency's investigative methods, documented in this collection, were later adopted by public law enforcement units. Pinkerton's compiled dossiers on criminals, used mug shots for purposes of identification, cultivated informers who were given code names, sent operatives undercover to infiltrate gangs, and circulated notices to alert the public that criminals were at large.
Pinkerton's first big contracts were with railroad companies, and the Administrative File includes a copy of a contract signed in 1855 with the Illinois Central Railroad, whose legal counsel was Abraham Lincoln and director of security was George B. McClellan. Lincoln and McClellan later turned to Pinkerton for detective work at the outbreak of the Civil War. Allan Pinkerton's efforts to establish a secret service in 1861 to protect the president and provide military intelligence for the Army of the Potomac are documented in letterpress copy books. Although office files were burned in the Chicago fire of 1871, Civil War correspondence and a journal which Pinkerton had lent William Herndon survived.
Eight letterbooks supplemented by three investigative field reports comprised the collection processed in 1975. The first two letterbooks concern Allan Pinkerton's activities as head of the secret service for the Army of the Potomac and reflect the scope of activity performed during the early inception of this unit. They consist mostly of outgoing correspondence and reports addressed by Pinkerton under his wartime pseudonym, Major E. J. Allen, to various government agents and officials, including George B. McClellan and Andrew Porter. These reports summarize field investigations gathered by Pinkerton's operatives and largely concern incidents of sabotage and espionage occurring in the Washington, D.C., area. Copies of incoming letters are included, as are private letters written under Pinkerton's own name. A letter dated October 6, 1861 to John Dewe reveals Pinkerton's personal convictions as to the necessity of preserving the union and abolishing slavery.
A daily journal of the New York office, 1865-1866, contains reports, letters, interviews, telegrams, and assignments of operatives. Letterbooks of George H. Bangs, general superintendent of the New York office for many years, document the day-to-day functions of the agency. Bangs's letters to Pinkerton relate the progress of specific investigations and details of general administration. His letters to district superintendents concern operational policy ranging from office management to investigative procedures.
Allan Pinkerton's letterbooks contain family as well as business and administrative correspondence and provide insight into the tactical methods employed by the agency under his direction.
The investigation of the Molly Maguires was the last important case that Allan Pinkerton personally supervised. The Molly Maguires were a secret organization of Irish immigrant coal miners who used violence and intimidation to battle low wages, poor working conditions, and ethnic discrimination in the anthracite fields of Pennsylvania. A report dated January 24, 1875 and sent to Franklin Gowen, president of the Reading Railroad, by Benjamin Franklin, superintendent of the Philadelphia office, recounts the daily movements of James McParland, the Pinkerton operative who infiltrated the Molly Maguires. This report and two others concerning labor unrest and unionization in the Pennsylvania coal region complete the collection as it was in 1975. Since these reports were microfilmed with the letterbooks, they remain with the material processed in 1975 despite the addition of related items in the Criminal Case File.
The Administrative File series also includes rules of conduct and a code of ethics communicated to his employees by Allan Pinkerton in essays entitled, “General Principles.” Pinkerton determined that the agency would not undertake an investigation on behalf of a defendant in a criminal case, would not conduct investigations involving the activities of public officers, or investigate parties suing for divorce. Pinkerton's agency did investigate labor unrest and was involved in strikebreaking at mining operations and related industries, though very little documentation of these activities is in the collection. The agency stated that records of such operations were returned to clients. The Molly Maguire reports are supplemented by material in the Criminal Case File series. A report dated 1874 on the Cambria Iron Works in Johnstown, Pennsylvania, is also in the Criminal Case File series. In addition, records from Robert Pinkerton's testimony on industrial espionage during Congressional investigations in the 1930s are part of the Family Director's File.
Pinkerton's had serious competition by the beginning of the twentieth century, especially from the agency headed by William Burns, a successful private detective. Pinkerton's criticized Burns's investigative methods, particularly his use of wiretaps, and the moral character of his operatives, some of whom had criminal records. For several years, Pinkerton's investigated the Burns agency and worked with a legal team that charged it with improper conduct. Records of the William J. Burns International Detective Agency investigation and subsequent hearings before the New York State Comptrollers office are included among the Administrative File series.
Although the Criminal Case File series represents only a fraction of the company's business, these cases received extensive publicity even many years after being solved. Pinkerton's archive was the source for many popular detective stories. As a consequence, newspaper and magazine articles sometimes dominate the case files. Most cases, however, are documented with at least some items created during the investigation, including correspondence, reports from operatives, mug shots, reward notices, and wanted posters. Some cases include legal documents and police and prison records such as Bertillion charts, which recorded bodily measurements and physical descriptions as the primary means of identification before fingerprinting became standard in the twentieth century.
Pinkerton officials wrote essays about their important criminal cases for exhibitions, publicity, or simply to create a narrative account of events. Records identified in the Criminal Case File as essays and notes are usually items created by the agency itself. However, the agency did hire professional writers, or allowed them access to the “secret archive” as this collection was sometimes styled, and drafts of their essays may also be included in the files.
Cases are arranged alphabetically by the name assigned by the Pinkerton agency. Some cases are identified by the name of the criminal or gang of criminals. Pinkerton's used the legal name of the criminal, in so far as it could be established, and not a more commonly known alias. Other cases are identified by the name of the victim, such as a train, bank, or jeweler, or a murder victim. For instance, the serial-killer Herman Mudgett was first investigated by Pinkerton's for insurance fraud after he filed a claim when his business partner, Benjamin Pitezel, appeared to have died in an office fire. The case is identified as the Pitezel murder, but the file more fully documents Mudgett's sensational life of crime. Crimes committed by a group of cowboy criminals are subsumed under the entry for Butch Cassidy and the “Wild Bunch,” the name given to the cattle thieves, bank and train robbers, holdup men, and general outlaws congregating in the Hole-in-the-Wall country of Wyoming where, commencing in 1897, they came under the leadership of Robert Leroy Parker, alias Butch Cassidy. Butch Cassidy and the Sundance Kid have been identified in the files by their criminal names, an exception to the usual practice, since these names conform to authority files established at the Library of Congress.
Since gang membership was not necessarily fixed or exclusive, records for some criminals are in several case files. Card indexes created by Pinkerton's to cross reference gangs and individuals are in the Administrative File. The indexes sometimes cite a “binder number,” the numerical filing system first established in the 1930s when a Pinkerton manager, Ralph Dudley, began compiling the corporate archive by gathering case material into expandable binders. The case files have been reorganized in an alphabetical arrangement, but if the index refers only to a binder number, the numerical list of binder titles at the beginning of the index can be consulted to determine the case name.
The 2020 Addition consists of draft manuscripts and printing plates. The draft manuscripts include eight detective stories, likely intended as chapters in a longer published work, all unsigned and undated, though possibly written by Allan Pinkerton (1819-1884) and Allan Pinkerton (1876-1930) or professional writers. An additional manuscript, an untitled draft of an incomplete novel, is the original version of a photostat received in a previous accession. Also included are eight printing plates. Of these, five are block printing plates with images of Allan Pinkerton, William A. Pinkerton, and Robert A. Pinkerton, possibly used as letterhead or logos on agency stationery, two are engravers copper plates of calling cards for Joan A. Pinkerton and Mrs. Kate Warn, and one is a block plate celebrating the agency's 100th anniversary.