Cat Defenders, a group set up in the wake of two cats being shot dead in Exeter, believe they know who the shooter is.
Information received on the Cat Defenders hotline in Exwick, set up after the shootings, also indicates where the culprit may live.
The reward offered by the group for the successful prosecution of who is behind the killings now stands at £750.
The Cat Defenders co-ordinator, who has asked not be named because of the fear of reprisals, said: " The response has been excellent.
"We have had numerous tips, including one particular name that has been given to us twice. We also now have a very good idea of where the shooter lives."
The group are now working closely with the police to corroborate reports and information.
They are also making use of specialist equipment and investigative skills, which members of the group have brought forward to help further the investigation.
Recently, the Exwick Cat Defenders also started a leaflet campaign to raise awareness of the threat posed by the cat killer and to appeal for information.
This comes at a time when some reports suggest that the killer is not just targeting cats, but other wildlife as well.
Some people have also come forward to say that they have heard gun-fire in areas where members of the public frequently walk, which, according to the co-ordinator, shows a flagrant disregard for the safety of others.
She said, "Several people have reported hearing an air weapon being discharged in a specific area, even while people have been walking there which clearly shows how reckless, or malicious, the shooter is."
She added that anybody with information could come forward anonymously:
"If anyone has any information that they haven't yet called in, please do so. Don't worry about possibly repeating information that we might already have, all information is useful.
"The reward for information leading to a conviction: the fund is currently at £750 -- but if anyone else feels able to pledge a contribution to the reward fund, we'd love to hear from them too."
You can contact the Exwick Cat Defenders Hotline by calling 07974 518036.
