[4] In the 1890s "he had a Fifth Avenue house and was known for his trotting horses, his diamond studded walking stick, his appearances as a man about town.

[9][10] During 1915, Lamar acted as an agent for Franz von Rintelen, a captain in the intelligence wing of the German Imperial Navy who operated covertly in New York City.

Lamar promoted strike action and work stoppages in munitions factories by means of the Labor's National Peace Council.

[11] From offices at 55 Liberty Street, Captain von Rintelen spent US$500,000,[12] much of which went to Lamar, whose reports of his success were greatly exaggerated.

[14] In 1923 after losing an appeal on a conspiracy charge, he fled New York City and was found 8 months later in Mexico and sent to the Essex County Penitentiary in North Caldwell, New Jersey,[15][16] for one year for being involved in strikes in munition factories; he was released in 1924.