In 1946, Ciupercă joined the anti-communist Graiul Sângelui organization. Due to this and to his association with the Romanian invasion of the Soviet Union, on 12 September, 1948, the retired general was arrested and tried by the Bucharest People's Tribunal. He was sentenced to 12 years in prison for conspiring against the Romanian People's Republic and conspiring against the social order. He was sent to Jilava prison, where he was severely beaten. From there, he was transferred to Văcărești prison in the southern outskirts of Bucharest. Due to failing health, Ciupercă was admitted to the medical wing of the prison, where he died on 25 May, 1950, being ill with cerebral atherosclerosis, Parkinson's disease, myocarditis, and azotemia.