Several kangaroos and wallabies have been found "mutilated and tortured" in Appin in recent months.
Now wildlife rescue volunteers want your help to catch the person or people responsible.
Two swamp wallabies were found decapitated with their tails removed alongside Appin Road this week.
Sydney Metropolitan Wilidlife macropod coordinator Jamie Ilo said this bought the number of mutilated animals found in the area to seven.
"They are all found within a couple of hundred metres of the roundabout as you come into Appin which makes me think they were killed elsewhere," he said.
"You do see kangaroos around Appin occasionally but swamp wallabies tend to live in the bush.
"These are definitely not injuries caused by a car accident - these are injuries deliberately done by humans."
Mr Ilo said he could only speculate as to whether it was the same person involved in the spate of attacks.
"I can't say for sure but the injuries are very similar," he said.
"It's relatively easy to catch swamp wallabies, but even I wouldn't want to handle a fully-grown eastern grey kangaroo on my own and I am trained to handle them.
"It makes me think a group of people may be involved."
Earlier this year two Eastern Grey Kangaroos had been beaten and had their tails removed in what Mr Ilo described as a "brutal" attack.
These animals were also found along the same stretch of Appin Road.
Mr Ilo said residents reporting the incident were concerned that the violence against these animals could escalate.
"We have the police involved and the detective working with us from Campbelltown Local Area Command is amazing but we want the public to keep an eye out too," he said.
"If you hear or see anything strange, if you have any dash cam footage that might help, please report it to the police."
Mr Ilo said locals should report any sightings of mutilated wildlife to the police and Sydney Wildlife at: 9413 4300.