Denounced to the Soviet authorities, arrested, and interrogated for six months by the Soviet NKVD, Kasparek was sentenced to eight years in Soviet "Gulag" forced labor camps, called "łagry" by the Poles. His pregnant wife had already been deported to Kazakhstan; their first daughter would die there at age two of pertussis. Kasparek himself barely survived two years' hard labor, emaciation and near-fatal typhus before being "amnestied" with other Poles by the Soviets after Hitler's invasion of the Soviet Union (June 1941).