A bin bag of cats' heads found on a street in "an extreme example of animal cruelty" could have been "racially motivated".
A council cleaner in Manchester was called to the "sickening" incident in an alley just off Wilmslow Road, a spokesman for Manchester City Council said.
He added that the area is known as "Curry Mile" as there are lots of Indian restaurants, but said the council is not connecting the incident with any of the businesses in the locality.
The council spokesman said the incident could have been "maliciously" or "racially motivated".
There are believed to have been around four or five heads in the bin bag.
On its Facebook page, the council said: "This is obviously an incredibly distressing and sickening incident which we are now looking into but this is the first incident of its kind we have come across.
"At this stage we have no way of knowing how these animal parts came to be where they were discovered but we will be contacting the RSPCA as this is clearly an extreme example of animal cruelty."
Cathy Hyde, RSPCA chief inspector, said: "This sounds like a very distressing incident, especially for the people who found the remains.
"Thankfully reports like this are extremely rare and we will liaise with the local authority to look into this further.
"I would appeal for anyone with information about this call the appeal line on 0300 123 8018 and leave me a message."