Under the Soviet government he was able to legally register in 1945 as a priest in Rivne, in what is now Ukraine. He centered his ministry in Volhynia, while also travelling to the Latvian and Lithuanian territories of the Soviet Union.
In 1958 Soviet authorities stripped him of the right to publicly perform priestly functions, and he began ministering secretly in Ukraine, Belarus, Lithuania, and Estonia. In 1963 he went to Kazakhstan, where the Soviets had deported tens of thousands of Poles. He continued to minister in secret, while publicly working at a bookbinders'.
He was arrested in 1966 and sentenced to prison, but he escaped the following year and continued working as a priest in Kazakhstan.
Suffering from tuberculosis and progressing deafness, Fr. Serafin was able to return to Poland, then a Soviet satellite state, for hospital treatment in 1968. He had lung surgery in Wroclaw, and returned to Kazakhstan in June 1970.
The priest then ministered primarily in Kazakhstan and Ukraine until his Sept. 20, 1977 death, while reciting the breviary, in Lviv.
Although his cause for sainthood is in still at an early phase, Fr. Serafin is honored by the families of those he served in Ukraine and in Kazakhstan, many of whom have preserved the private altars where the priest would celebrated Mass in their homes.
Pope Francis gave the green light for Fr. Serafin's cause to move forward during an Oct. 9 meeting with Cardinal Angelo Amato, Prefect of the Congregation for the Causes of Saints.
Other causes the Pope advanced include the martyrdom cause for Franciscan priest Fr. Tullio Maruzzo and Third Order Franciscan layman Luis Obdulio Navarro, who were killed in hatred of the faith July 1, 1981, near Los Amates, Guatemala.
Formerly Servants of God, the approval of Maruzzo and Navarro's martyrdom has opened the door for their beatification, which would allow them to be called “blessed.”
In addition to the martyrs and Fr. Serafin, Pope Francis recognized the heroic virtue of six other causes: those of layman Francesco Paolo Gravina, founder of the Congregation of the Sisters of Charity of Saint Vincent (Italy); diocesan priest Fr. Donizetti Tavares de Lima (Brazil); Sr. Magín Morera y Feixas of the Congregation of the Holy Family of Jesus, Mary and Joseph (Spain); María Lorenza Requenses de Longo, founder of the Hospital of the Incurables in Naples and of the Capuchin Nuns (Italy); Françoise du Saint Esprit, founder of the Third Order of Saint Francis in Montpellier (France); and El?bieta Ró?a Czacka, founder of the Congregation of the Franciscan Sisters Servants of the Cross (Poland).