The discover of a pet cat apparently thrown into the Swan River with a brick ties around its neck has left locals reeling and angry.

The RSPCA is now hoping to gather information that could lead to the identification of those responsible.

Press PLAY to hear more about the shocking act of cruelty

RSPCA Inspector Hayley Wirth told Gary Adshead on 6PR Mornings the act of cruelty has had a massive effect on the owners.

“I will never forget their reaction when I had to break the awful news to them,” Ms Wirth said.

WARNING: DISTRESSING IMAGES

Anyone who has information on the senseless act is urged to contact the RSPCA on 1300 278 358 or at rspcawa.org.au.