General Reginald Dyer was never formally tried in a court of law for his actions during the Jallianwala Bagh massacre in 1919. After the incident, a Hunter Committee condemned his actions but did not impose any legal punishment. Instead, the Commander-in-Chief of the Army directed Dyer to resign his position as Brigade Commander and informed him that he would receive no further employment in India. He was effectively removed from command and forced into retirement.
A later significant legal case indirectly related to Dyer was a defamation trial in London concerning Michael O'Dwyer (the Lieutenant Governor of Punjab who had approved Dyer’s actions). In this case, O'Dwyer sued Sankaran Nair for defamation over a book that criticized the massacre. Dyer was too ill to attend this trial, which took place years after the massacre, and the trial assessed the conduct of both O'Dwyer and, by extension, Dyer's role. The verdict favored O'Dwyer, with the judge sympathetic to Dyer's actions, expressing the opinion that under the grave circumstances, Dyer had acted rightly and was wrongly punished by the Secretary of State for India.
In summary, General Dyer was forced to retire and no court formally tried him for the massacre, and subsequent legal proceedings around this period did not condemn him but rather showed sympathy toward his actions.