father Mr. Boone. And here is why.
In the book there is a line that Mr. Boone says to Christopher that is a bit suspicious and led me to believe he was Wellingtons killer. The said " Just try to keep your nose out of other peoples business.'' Only a guilty person would want to keep other people out of their business. If someone had nothing to hide they would have no problem letting someone else try to investigate.
Knowing that other people can believe that possibly christoper or mrs shears where the one to kill wellington, i will tell you why it was not them. mrs shears had no reason to kill her own dog. when christoper saw the dog he said it looked like it had been killed recently and when mrs came out she did not seem like she had been up. plus no sane person ever just randomly kills they're own dog. chris is incapable of lying so he did not kill the dog, plus someone that is working so hard to find the killer cant have killled the dog otherwise they would killed him and never spoke about it again.
therefore mr. boone was they only one that could have killed him, the motive could have been many things stress about having an autistic son that can never love you the way you live him, and the fact that hes a single father, or the fact that he could have been intoxicated with something weather that is with beer, or drugs. Or some type of affair with Mrs sgears that ended badly as they were seen hugging a little more friendlier that normal. Mr Boone killed Wellington.
