CAN.1707 $1. Whenever the death of a spouse cannot be proven by an authentic ecclesiastical or civil document, the other spouse is not considered free from the bond of
marriage until after a declaration of presumed death is made by the diocesan bishop.
$2. The diocesan bishop can make the declaration mentioned in $1 only after appropriate investigations have enabled him to attain moral certitude of the death of a spouse from
the depositions of witnesses, from rumor, or from indications. The mere absence of a spouse, even for a long time, is insufficient.
$3. The bishop is to consult the Apostolic See about uncertain and complex cases