Udham Singh was an Indian revolutionary belonging to the Ghadar Party, best known for his assassination in London of Michael O'Dwyer, the former lieutenant governor of the Punjab in India, on 13 March 1940. The assassination was done in revenge for the Jallianwala Bagh massacre in Amritsar in 1919, for which O'Dwyer was responsible. Singh was subsequently tried and convicted of murder and hanged in July 1940. While in custody, he used the name Ram Mohammad Singh Azad, which represents the three major religions of Punjab and his anti-colonial sentiment.