Detective Chief Inspector Craig Nicholson said: “Officers are currently on the path near to the old railway track at Louth Road, New Waltham.
“A report was received at around 6.45am today (April 25) of a discovery of what was believed to be a human body part.
“We are in the very early stages of the investigation. However, it is suspected to be a lower limb.
“A cordon is in place and people are asked to please avoid the area and allow officers to carry out enquiries as part of the investigation.
“Anyone with any information is asked to call our non-emergency number 101 quoting log 85 of 25/04/19.”
You can also contact Crimestoppers anonymously on 0800 555 111 with any information.