Sidney F. Mashbir, was born in Manhattan, New York City, New York on September 12, 1891, but later moved to Safford, Arizona in 1899.[5] Sidney's Father was Professor Eliazar S. Mashbir, a Russia immigrant who was well-educated and became the first Russian-speaking attorney to practice Law in New York City. Sidney's Mother, Frida Freudenthal was also well-educated[6], and in 1906 became the Postmistress of Safford, Arizona which included the area of Solomonville, Arizona.
Mashbir attended public schools in Safford, Arizona and later studied engineering at the University of Arizona for six months each year until 1911 whilst maintaining a career as a Engineering Draughtsman, primarily for the engineering department of Safford, and railroad companies.[5] Sidney Mashbir married his first wife Miss Blanche Beckwith on September 12, 1913, however the two separated during the 1920s.[5] [7]
Early service
Sidney F. Mashbir joined the Arizona National Guard at a young age, and served as a bugler of Company B in 1904.[4] He later became the First Lieutenant and Adjutant of the University Battalion whilst studying at the University of Arizona.[5]In 1912, he served as a Lieutenant in Company K of the Arizona National Guard encampment, which based at Fort Huachuca. The senior instructor at the time was Captain Louis Joseph Van Schaick.[4] [5]
In early 1916, Mashbir received his first official intelligence assignment, when he was assigned as the Assistant Intelligence Officer of the Ajo-Yuma district of Arizona as apart of the first Arizona Infantry under General Frederick Funston. His duties included mapping roads, trails and waterholes in northern Sonora. Additionally he would scout Mexican towns with Papago Indian scouts, reporting on the strength and equipment of Mexican garrisons and installing primitive wiretaps on Mexican communication lines. Mashbir was also responsible for investigating Japan's physical presence in Mexico at the time.[4]
In late 1916, Mashbir applied for a commission in the Regular Army and was accepted with General Funston's support despite the Army’s policy that married men not be accepted. After attending the Army Service Schools at Fort Leavenworth, he joined the 22nd Infantry Regiment, which was stationed at Governors Island, New York, but was soon detailed for counter-espionage duty and was recommended to join a new Counter Intelligence service that was being formed.[4]
On 10 September 1917 he was detailed as assistant to the Department Intelligence Officer at Governors Island. He enrolled in the Military Intelligence Division G-2 Reserves and become a Lieutenant Colonel (temporary rank). During this time he wrote the Provisional Rules for Counter Espionage, Eastern Department, which would become a model for future counterintelligence manuals and survive until World War II[4] as well as a 52-page book titled Ten Lessons in Bayonet Fighting published by George Banta Publishing Company at the end of 1917.[8]
Mashbir's is also credited with the investigations as a Coast Defense Intelligence Officer at Fort Hamilton which uncovered the first German spy to be apprehended in the United States, Paul Otto Kuhn.[4]