Police are concerned for the welfare of a man who was last seen walking his dog in Skegness.
David Leman, 51, parked his car in South Parade car park in Skegness on Monday morning and took his dog, Millie, for a walk.
Millie was found later that day with her lead attached but David is still missing.
He is of mixed race, approximately 6 foot tall with a shaven head.
His clothing has not been confirmed but is thought to be jeans and a hooded jacket.
Police would particularly like to hear from any dog walkers who may have seen David and Millie yesterday morning.
Millie is a black dog with a white patch on her chest and she was wearing a red collar.
Anyone with information should contact Lincolnshire Police on 101, quoting the incident number.
The Coastguard helicopter and search teams have been searching for David overnight and will continue throughout today. Louth Search and Rescue Dogs are attending to assist.