A Lincolnshire Police spokesman said: “We can confirm that we have received new information about the disappearance of Michael Hewerdine, who was last seen at his home in Ruskington on November 21, 1996.
“An investigation has been underway since this date, which police are now dealing with as murder, and now believe that the remains of Michael could possibly be buried in East Heckington.
“We have today (Tuesday) started an excavation in a field of an address on the A17 at East Heckington, between Swineshead Bridge and Sleaford.”
Detective Chief Inspector Martin Holvey, of the East Midlands Major Crime Unit, explained: “Investigations of this kind are continually reviewed and cases of this nature are never forgotten. As part of our enquires we have identified new witnesses and leads which has led to us carrying out this work.
“We have sought consent from the land owner to undertake this work and I would like to thank them for their co-operation, particularly as they have only moved into this address in the last few years.
“The owners are not part of this investigation, so please respect their privacy while this work is ongoing. We anticipate the excavation will take between one and two weeks, and we will update on our progress.
“I would urge anyone with any information or knowledge about how Michael disappeared who has not already come forward, or who has information they have not previously told the police, to contact my investigation team.”
Michael’s sister, Madeleine Judd, is appealing for anyone with information to come forward: “My brother Mick has been missing for 20 years.
“He was born and brought up in Ruskington and most of his friends knew him as ‘Hewey’. He could often be seen at the local pub playing darts or snooker - which he was quite good at and won trophies for.
“We as his family really need closure. His mother, myself and his daughter - we all really need to know what has happened to him, so if you have any information whatsoever, please contact the police.”
She also gives a video appeal on the 20th anniversary of Mr Hewerdine’s disappearance.
Anyone with any information should call 101 referring to incident 97 of 31/10/16 - or anonymously through Crimestoppers on 0800 555 111.