The Sentinel and Enterprise of Fitchburg reported Friday that the "V" sightings began Sept. 30 when a group of teenagers began wearing the masks to scare one another.
But one teen got carried away and began peering into residents' windows. Groton police assisted in the probe following a similar report from Shaw's supermarket.
Police did not identify the main suspect they said was not arrested but will face a charge of disorderly conduct for scaring and alarming his neighbors.
"V for Vendetta" was adapted from a graphic novel about a masked freedom fighter battling British fascism in the near future.