A dog found with a knife lodged in his neck has had to be put down after becoming "increasingly out of control" and aggressive towards rescuers.
Aslan, a four-year-old Johnston Bull Terrier, was found bleeding from the neck and head area in Edinburgh on January 7.
A Scottish SPCA inspector took the dog to a vet, where a 26cm blade was found lodged in his neck.
He immediately underwent surgery and for the next few days was in a stable condition and responded well to treatment.
However, when Aslan was moved to the charity's animal rescue and rehoming centre in Cardonald, Glasgow, on January 11, he began to act aggressively towards members of the team and it became impossible for even experienced members of staff to interact with him.
He did not react well to attempts to physically examine him and had to be heavily sedated for this to take place.
The Scottish SPCA said it took the decision to end his life "with a heavy heart" after it became clear he was a danger to staff and could not be found a new home.
Mike Flynn, Scottish SPCA chief superintendent, said: "We continued to try to help Aslan as best we could and monitored his behaviour closely over the following days. Unfortunately, he grew increasingly out-of-control.
"It became clear that to ask anyone to interact with Aslan would be to ask someone to put their life at risk.
"It also became clear that, even with all the support we could give him over as long a period of time as needed, Aslan would still not be able to join the loving home every animal deserves.
"At the Scottish SPCA we are proud of our commitment to never put a healthy animal to sleep and every year we successfully help thousands of animals rehabilitate, both physically and mentally, and join loving homes. No matter how long it takes.
"In a very small number of cases we are, however, not able to achieve this happy outcome.
"In these difficult situations we have a responsibility to make the right decision for an animal's welfare and for the people with whom he or she comes into contact.
"To confine an animal to a kennel for the rest of its life, with little to no interaction with people, is no life at all. This would have been the future Aslan faced.
"It is with a heavy heart that, following consultation with very experienced members of our animal welfare team and our chief veterinary officer, we have had to take the difficult decision to end Aslan's struggle in life."
The charity said it is still investigating what led to Aslan being stabbed in the first place.
The organisation said Aslan was at his most relaxed in its sensory garden and will come up with a way to honour his memory as it expands the garden in the near future.
Anyone who has come into contact with Aslan previously or has any information which they feel could help the investigation is asked to call the Scottish SPCA's animal helpline on 03000 999 999.