Using a meticulous planning system called "The Lamm Technique", he conducted dozens of successful bank robberies from the end of World War I.

[5] Lamm became a holdup man, and quickly started adapting his military training, his study of tactics, and his precision and discipline into the art of crime.

He theorized that a heist required all the planning of a military operation, which included the development of contingency options in the event of unforeseen problems.

[2][5] Bank robberies in the United States were largely improvised at the time, resulting in varied degrees of success and failure among heists.

Lamm pasted a chart on the dashboard for the driver, which included block-by-block markings of escape routes, alternative turns and speedometer readings.

[5] Using this system, Lamm and his gang conducted dozens of successful bank robberies from the end of World War I to 1930, taking more than $1 million in total.

In a bond hearing to determine Lamm's fate (he was using the alias "Robert J. Masden" at the time), evidence showed that he was arrested in San Francisco in December 1914 (under his actual name), on a charge of robbery, but there was no known disposition of the case.

[3] After stealing $15,567 from the Citizens State Bank, getaway driver and ex-rum-runner W. H. Hunter noticed a local barber approaching the car with a shotgun.

[4] Two survivors of Lamm's gang, Walter Dietrich and James "Oklahoma Jack" Clark, were captured and eventually sentenced to life in an Indiana state prison.

[6] Infamous bank robber John Dillinger studied Lamm's meticulous bank-robbing system and used it extensively throughout his criminal career.