Arrangements are being made for a meeting between Pope Francis and a former Japanese death row inmate during the pontiff's visit to Japan in November.
Iwao Hakamada was sentenced to death for the murder of a family of four in 1966, but was later freed after spending decades behind bars. The 83-year-old has been claiming his innocence and seeking a retrial.
Pope Francis is opposed to the death penalty. In March last year, he revised the Catholic Church's teachings, and declared that the death penalty is inadmissible. He said the Catholic Church will work toward its abolition around the world.
Vatican sources say arrangements are being made for a meeting between the two on November 25 in Tokyo.
Observers say the meeting could draw the world's attention to Japan's system of capital punishment.
Pope Francis will be the first pontiff to visit Japan in 38 years. During the four-day visit that starts on November 23, the pontiff will remember the victims of the 1945 atomic bombings in Hiroshima and Nagasaki and hold masses in Tokyo and Nagasaki.
Hakamada's older sister, Hideko, says her brother was christened at the Tokyo Detention House. She says she sent a letter to the Pope in May asking for a meeting with her brother in Japan even if it is only for a minute. She says it will be the greatest gift for her brother if the meeting takes place.