Immediately before the war he became the secretary of the committee for the third region of the KPH in Zagreb.
After occupation and formation of the Independent State of Croatia, Marijan Čavić organized illegal work in his area and participated in sabotage and other actions.
Wanting to extort a confession from him at all costs, the police sent him to the Karlovac hospital for treatment.
Partisan rescue operation under command of Većeslav Holjevac enter to Karlovac but did not succeed, because in the meantime the Ustashas returned him to prison, so Holjevac and his Partisans did not find him in the hospital.
Marijan Čavić was taken to the Jasenovac concentration camp where he was killed at the end of 1941.