Kowalczyk brothers

Ryszard Kowalczyk (20 February 1937 – 18 October 2017) and Jerzy Kowalczyk (born 1942) are Polish brothers who planted a bomb as a protest against the communist rule in Poland. The Kowalczyk brothers were scientists at Opole University. They were born in Warsaw.
Bombing.
On 6 October 1971 as a protest specifically against the violence perpetrated by the communist authorities against a large workers' protest. The big explosion destroyed the university hall where the celebrations were to take place.
Pardoning.
With the rise of Solidarity in the 1980s, pardons were issued and the brothers were freed for good behavior: Ryszard in 1983 and Jerzy in 1985. In 1991 President Lech Wałęsa decided that their sentences were legally "forgotten" which would allow them to work again.
Life.
Ryszard Kowalczyk died on 18 October 2017 in Warsaw at the age of 80.