A Romanian baby died after a baptism ceremony in which babies are immersed in holy water three times.
The 6-week-old baby was rushed to a hospital with cardiac arrest on Monday and died a few hours later, the autopsy revealed fluid in his lungs, Agence France-Presse reported.
The tragedy put pressure on the Orthodox Church to change the rules of baptism.
Prosecutors opened an manslaughter investigation against the priest in the city of Suceava.
“The death of a newborn baby because of this practice is a major tragedy,” said a message with an online petition for changes to the ritual. “This risk must be ruled out if the joy of baptism is to triumph.”
On Thursday night, the petition gathered more than 56,000 signatures, according to AFP.
One online person denounced the “brutality” of the ritual and another criticized the “stubbornness of those who think it is God’s will” to keep it.
Local media reported several similar incidents in recent years.
Church spokesman Vasile Banescu said priests could pour a little water on a baby’s forehead instead of total immersion.
But Archbishop Teodosie, leader of the Church’s traditional wing, stood firm and insisted that the full ritual would not change.
In Romania, where more than 80% of the population is orthodox, the Church is one of the most trusted institutions, according to recent opinion polls.