Bobby, a small Shetland pony, was found dead in a field off Cleadon Lane, Cleadon, by his heartbroken owner Wendy Redpath on Thursday evening.
The 12-year-old pony - who had been taken in by Mrs Redpath and was handicapped by foot problems - had been severely mutilated.
His genitals and bottom lip had been hacked off, his stomach slashed and his mane was cut off.
The sheer brutality of the killing left our readers shocked and disgusted – with hundreds of people taking to social media to express their horror and to plead for anyone for information to come forward.
A crowdfunding page has raised over £1500 for a reward to help catch the killer.
Police say the multiple injuries were caused deliberately.
The RSPCA has carried out a post mortem and it's believed he may have died up to 24 hours before he was found.
Northumbria Police say officers are investigating and also working with the local equine community.
Superintendent Brad Howe said: "This is a truly horrific crime which has understandably shocked the community.
"We know Bobby's owner is absolutely devastated and have been in regular contact with her to keep her updated with the progress of our investigation.
"We are continuing to carry out enquiries and are pursuing a number of lines of enquiry but need the public's help. Someone must know who did this, if anyone has any information about who is responsible we want to hear from them or if they saw anything suspicious in Cleadon Lane in the 24 hours before Bobby was found on Thursday evening please get in contact.
"We taking this incident very seriously and our enquiries will continue until we find who did this."
Readers have rushed to comdem the attack.
Laura Hanson posted: “Absolutely barbaric. Heartbreaking. Let’s hope those responsible are found very soon.”
Paul Jordan added: “Disgusting. This person needs caught. The fact they’re still out there is scary.”
Kevin Ball wrote: “Someone must know who did this. Do the decent thing and report it to the police. Let’s hope they are caught, named and shamed and the courts hand out a lengthy prison sentence, instead of the usual slap on the wrist for cruelty to animals.”
Mrs Redpath said: “I still can’t understand why anyone would do this. I’m finding it all really hard.
“I knew the horse community would offer support, but the wider public coming forward and offering money for a reward to catch those responsible, it’s just overwhelming.
“Everyone is concerned that these people could do it again. No one knows if this was a one-off.”
Anyone who would like to add to the reward total visit www.justgiving.com/crowdfunding/BobbyPony.
People with information on the killing is asked to contact police on 101 quoting reference number 1050 03/11/16.
They can also call Crimestoppers anonymously on 0800 555 111