She was arrested in December 1941 and convicted of failing to register as a paid Nazi agent, and served 20 months in prison.

Martha was the daughter of David Harrison Houghtaling of Kingston, New York, who was a descendant of Jan Willemsen Hoogteling, who arrived in New Amsterdam on May 9, 1661.

In late September 1939, Ingalls flew over Washington, D.C., in her Lockheed Orion monoplane, dropping anti-intervention pamphlets.

[4] Following the defeat of France in 1940, she approached Baron (Freiherr) Ulrich von Gienanth, the head of the Gestapo in the US, and, officially, second secretary of the German Embassy.

She had made a careful study of Mein Kampf, on which she based many of her speeches, as well as pamphlets by Hitler such as My New Order and Germany and the Jewish Question, and Elizabeth Dilling's books The Roosevelt Red Record and The Octopus.

After the German declaration of war on December 11, 1941, she went straight to Washington to receive a list of contacts from von Gienanth, and was arrested a week later.

[8] She was transferred from the District of Columbia jail to the U.S. federal women's prison in Alderson, West Virginia, on July 14, 1943, after fighting with another inmate.

A few months after her release, she stated her opinion of the Normandy landings: This whole invasion is a power lust, blood drunk orgy in a war which is unholy and for which the U.S. will be called to terrible accounting...

Her suitcase contained seditious materials, including notes she had made of Japanese and German short-wave radio broadcasts.