When the British Govt implemented an act to suppress freedom struggle, it gave the British Police a free hand to carry out arrests without any permissions. In order to protest against this act, Bhagat Singh and his friends carried out a plan to use low intensity bomb inside the assembly hall and at the same time ensure that there are no deaths. Immediately after the bombing, Bhagat Singh and his friends voluntarily surrendered and taken to trial. They were charged with attempt to murder and sentenced to 14 years life in 1929.
Further investigation by the Police led to discovery of other members, some of who turned into informants and helped police to connect Bhagat Singh with an alleged murder of a British Officer. Singh was again arrested and sent to another jail where he faced discrimination between British & Indian prisoners and that led to his protest in the form of huger strike against the discrimination.
In the meantime, the ongoing investigation of framing Bhagat Singh for the alleged murder of a British Officer in the past was hastened by the Viceroy, Irwin in 1930. Bhagat Singh, Rajguru & Sukhdev were sentenced to death and the execution date was fixed to 24th March 1931. The Congress and Gandhi made some attempts to save the lives but went in vain. Gandhi finally came to an agreement in the Gandhi-Irwin pact which gave the British the go-ahead with execution of Bhagat Singh and his friends.
On 17th March, a telegram was sent to Home Dept preponing the execution date to 23rd March, and was hanged to death at 7.30pm on 23rd March 1931.