Windows at the Hitchin Rugby Club clubhouse were damaged in a spate of "unacceptable" criminal damage earlier this month.
A double-glazed window at the clubhouse on Old Hale Way, Hitchin was smashed between 11pm on Thursday, July 14 and Friday, July 15.
This followed an incident at around 12.30am on Monday, June 7 when another window was also smashed.
PC Martin Barringer, of Hertfordshire Constabulary's North Herts Safer Neighbourhood Team, said: "This kind of anti-social behaviour in our community is unacceptable and leaves the club with an unnecessary repair bill.
"I would like to hear from anyone who witnessed either of these incidents or has any information about them to get in touch."
Anybody with information about the incidents can contact police in Hertfordshire online (https://www.herts.police.uk/) or by phone on 101, quoting references 41/56469/22 for the July 14-15 incident, or 41/45350/22 for the July 7 event.
The police can also receive 100 per cent anonymous reports via CrimeStoppers online (https://crimestoppers-uk.org/) or by phone on 0800 555 111.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here