A knifeman stormed into a church in Warsaw and stabbed the dad of a priest to death.
The priest who came to his dad's aid was also attacked before police arrived at the scene.
After a struggle the attacker was detained by police and is now in hospital, Polish media reports.
The dad who was killed is said to be about 60 years old and had arrived at the church for confession, according to the Archdiocese of Warsaw.
The severity of the injuries to the priest has not been reported but he is said to be in a stable condition.
According to the news agency Reuters, police were informed at 6.55pm (1655 GMT) that a man was lying bloodied on a street in central Warsaw.
Paramedics were unable to revive him, the spokeswoman said.
The arrested man is thought to be around 40 years old. There was no suspicion of a terrorist motive or further danger to citizens, the spokeswoman added.
Police investigations at the scene are underway.
