An urgent search is under way for the mother of a newborn baby left outside a vicarage in a supermarket bag.
The little boy was pronounced dead after he was discovered by the vicar of St Peter's Church, Bramley, Leeds, on Wednesday morning.
It is not clear whether the baby was still alive when he was found in the Tesco bag-for-life at about 9.15am as the vicar was heading for a morning service.
Detective Chief Inspector Nicola Bryar, of West Yorkshire Police, said her priority was finding the mother as she will need medical care and support.
Speaking outside St Peter's Church, Ms Bryar said: “I really want to appeal for the mother of that baby to come forward. She's our primary concern at the moment.
“We are very concerned for her welfare. We are sure that she'll be in need of medical attention.
“She will certainly need some support.”
The detective said police were called by the vicar at 9.18am.
She said she believed the baby, who was found unclothed in the bag with the placenta, was left during the hours of darkness.
Ms Bryar said the vicar's wife came home at 10pm the night before and did not notice the bag then.
She asked for anyone who saw someone carrying a Tesco bag-for-life in the Hough Lane area between Tuesday night and Wednesday morning to come forward.
The officer said a post-mortem examination had not found the cause of death. She said the baby was cold to the touch when found by the vicar. Paramedics and doctors at Leeds General Infirmary tried to revive the youngster but without success, she said.
But the pathologist had not been able to determine when the baby died.
She said the baby was white, male and full-term.
Ms Bryar said of the mother: “She's certainly gone through a traumatic ordeal. She's given birth and hasn't sought any medical attention. But it's the support as well.”
Tributes including flowers, teddies and poems have been left outside St Peter's Church.
One message said: “Now you have your wings. Fly high into the arms of the Lord. God bless you little angel.”