Nazi symbols have been graffitied all over a memorial bench remembering those who gave their lives in World War II.
The white and silver graffiti was also found in a number of other areas in Twyford Woods, between Grantham and Stamford.
Swastikas have been sprayed in the park at some point between Sunday, June 10 and Monday, June 11.
Lincolnshire Police has launched an investigation into the incident after finding the bench “extensively” vandalised.
Anyone with information is being urged to contact the police on 101, quoting incident 54 of June 10.
If you would like to stay anonymous then contact Crimestoppers on 0800 555 111.