Forensic tests are being carried out after historic remains believed to be those of a baby were found at a house in Northamptonshire.
Builders made the discovery while renovating a cottage in the village of Sulgrave, near the Oxfordshire border.
Det Ch Insp Neil McMahon said preliminary inquiries suggested the remains may have been at the house for 100 years.
Officers want to determine whether the death was natural or unnatural.
The remains were found on Tuesday.
Det Ch Insp McMahon said: "The remains are believed to be those of a baby, however further work will now take place with forensic experts to establish the approximate age, and when birth and death would have likely occured.
"The premises have been receiving extensive renovation and are currently unstable, this is restricting our ability to complete a thorough search at this time.
"It is anticipated that the premises will be made safe, which will then allow us to complete a forensic search of where the body was found.
"One of the lines of inquiry will be to determine whether the death was natural or unnatural and the age of the body, which will help determine whether a criminal investigation will take place."