Menten moved to East Galicia in 1923 (then in Poland and later part of the Ukrainian Soviet Socialist Republic), where he became a wealthy landowner and businessman.

Described as mild-mannered and quiet, he developed a deep grudge against a prominent neighboring Jewish family over a business dispute.

The controversial trial concluded in 1949, with the prosecution unable to prove most allegations, and Menten was sentenced to an eight-month term for having worked in uniform as a Nazi interpreter.

His 20-room mansion was filled with valuable art work (Nicolaes Maes, Francisco Goya, Jan Sluyters, etc.)

During the trial, Menten's mansion was set ablaze after a survivor of Dachau concentration camp threw a petrol bomb onto its thatched roof.

[3] Upon his release in 1985, he believed he would settle in his County Waterford mansion in Ireland only to find out Garret FitzGerald, Taoiseach at the time, had barred him from the country.