The bodies of six domestic rabbits were discovered dumped in four supermarket carrier bags in a litter bin in Devon.
A council worker made the grisly find on Tuesday morning in St Michael's Park, in Paignton.
The RSPCA South Devon branch believe the animals – three tan-coloured with dark markings, one dark grey and the other two black – died at the weekend.
RSPCA chief inspector Neil Thomas said they may have suffered blows to the head.
"There is a significant chance these poor rabbits suffered before they died and we need to know what happened to them."