Villagers have been receiving death threats and menacing notes after several cars had acid thrown on them.
One of the notes sent to the homes in St Briavels, in the Forest of Dean depicts Prodigy frontman Keith Flint, who died in March, with the message: "We'll be seeing you soon."
The victims are all involved in carrying out local voluntary work.
CCTV images have emerged of a woman wearing a devil mask and a wig appearing to throw acid on cars.
The threatening notes to residents include: "Make sure the house is shut tight, something macabre watches us at night."
Another note depicts cockroaches, while another one stated: "It's nice to view you ... we get very excited when we discuss you."
Two people said they had received death threats via phone calls.
Parish councillor Andy Clarke said: "We're disturbed by the level of violence that has been occurring and now, the threatening letters.
"The vandalism is getting worse, everyone is shaken by the level of events."
'Shaken by events'
The acid attacks damaged six cars so badly they had to be written off.
Resident John Hurley said: "I feel sad there are people who are close to, or in the community who would do such a thing.
"A wonderful, peaceful, lovely little village - things like this don't happen.
"They do now obviously, but you don't associate acid throwing with this particular location."
Gloucestershire Police said it was investigating and urged anyone with information to contact the force.