WESTPORT — Reports of missing lawn signs and a mysterious group at the root of this has led police to open an investigation into the matter.

“Numerous claims of missing lawn signs have been reported over the past few weeks by local nonprofits. Some of these signs were displayed on private property or were authorized to be placed on public property,” Westport Police Information Officer Anthony Prezioso said in a news release on Tuesday.

According to police, a group calling itself “The Committee” has written to at least one local nonprofit organization stating if they fail to remove lawn signs, they will take them down “at first sight.” The individual or individuals have not identified themselves, but the incident is now under investigation.

Residents are advised against taking it upon themselves to remove signs that do not belong to them from public or private property.

“The removal of signs from public or private property by someone not authorized to do so by the town, or by the owner of the sign, may constitute theft,” Prezioso said. “Entering onto private property to remove signs may constitute trespassing. Both of these acts can result in arrest.”

Nonprofits are reminded signs advertising charitable events must be reviewed and approved by the town before the signs can be placed on town property or in the town right-of-way, police said. An electronic copy of the Temporary Sign Request form is available on the town’s website.

For each event, only a total of 15 signs are allowed on town property and in the town right-of-way. These signs cannot be placed out more than two weeks before the event, and must be removed within two days after the event, police said.

Anyone with information about the recent rash of missing signs is asked to call the Westport Police Department at 203-341-6000. Charities that have had signs removed from authorized public or private locations are also encouraged to file a formal police report.