The death of a newborn baby boy was caused by an obstruction of the airway, Lincolnshire police have said.
Officers released the detail after a 16-year-old girl was arrested in connection with the incident which happened in the early hours of September 5. She is currently helping officers with their enquiries.
Detective Chief Inspector Tony Heydon said: "Although we are unable to release any more detail at this stage we can reassure the public that we are not looking for outstanding suspects, we are simply gathering evidence and piecing together the sequence of events over the last couple of days."
More top news
Photos from a historic day in Scotland's history as voters choose to remain part of the United Kingdom.
Is Manchester really more powerful than Wales and Northern Ireland? Find out how the union's four nations compare with England's regions.
Hollywood director J.J. Abrams has been declared the victor in a good-natured Twitter war with his friend and fellow director Zack Snyder.