Career
Born in Siberia, where his family was deported to in 1949, Grantiņš came to Latvia in 1956. In 1986, he co-founded Helsinki-86. After having been imprisoned by Soviet authorities, Grantiņs went to Germany.
In 2013, Member of Parliament Valērijs Agešins asked to initiate criminal proceedings against Grantiņš, but the request was refused.
In July, 2015, Grantiņš has been detained in Latvia in connection to a criminal case on inciting national hatred. His attorney has complained on the circumstances of the arrest (Grantiņš had been injured).