Sinari was an active participant in Goa's struggle for liberation from Portuguese rule. He organized processions, rallies, and public campaigns, often affixing posters to promote the movement. He was arrested on three occasions, during which he faced physical abuse, including having his head shaved as a punitive measure. Sinari became a founding member of the
Azad Gomantak Dal (AGD), which broke away from the peaceful National Congress Goa (NCG) on 18 June 1947. In July 1947, AGD attempted to attack and steal from the Portuguese treasury, Fazenda, in
Mapusa. The only sentry guarding the Fazenda managed to defeat them, resulting in one Portuguese policeman being badly injured. Following this, the AGD unsuccessfully tried to rob bags of a cash from an officer of the Portuguese overseas bank,
Banco Nacional Ultramarino, while in a bus at
Porvorim. These actions led to increased persecution by Portuguese authorities. Sinari was known for his use of guerrilla tactics and leadership in armed operations, earning him the nickname "
Che Guevara of Goa" for his revolutionary activities and strategic acumen. Sinari was arrested for his involvement in these revolutionary actions. Following a trial by the Portuguese Tribunal Militar Territorial, he was sentenced to 13 years of imprisonment. While in detention, he endured
solitary confinement, inhumane treatment, and torture for refusing to recognize or respect the
Portuguese flag. == Leadership in armed operations ==