A baby whose body was found at a Lincolnshire recycling plant probably died after an "unprofessional attempt" at delivery, an inquest has heard.
The newborn boy, named Jacob by a local businessman who paid for his funeral, was discovered at Addlethorpe's Greenstar facility in October.
No cause of death was established but an expert said she believed he died in the birth canal or directly afterwards.
Coroner Stuart Fisher recorded an open verdict into the death.
The baby is thought to have been left in a wheelie bin in nearby Skegness before he was found in a bin liner at the plant. Medical tests showed he had not been stillborn.
Home Office pathologist Dr Elizabeth Turk, who carried out the post-mortem examination, told the inquest at Horncastle Registration Office that Jacob had a pair of jogging bottoms tied around his neck - consistent with an amateur delivery.
His mother has never been traced and no DNA matches were found on the national database, the hearing was told.
Det Insp Andy Wardell said the investigation had been "very emotional and very difficult" for officers.
Mr Fisher said the case was "deeply tragic" for both the baby and mother, and that he was satisfied police had made exhaustive efforts to trace the parents.
A funeral for baby Jacob was held at St Nicholas Church in Addlethorpe last month.