hmm...i was thinking of some ways:
1). Follow the street cats around and see whoever takes them away...we can catch them red-handed.
2). Put posters (an NUS/SIM/NYP effort?- how about roping in the animal-help club (dunno the name) saying if anyone seen suspicious people meddling with cats, call the police or alert someone?
Put the posters around JE. ==> This will cause, hopefully, the media to report on this, and generate news....at the same time, the media itself will then force the police to pull-up their socks and do something...