Centrella and a Teton County sheriff's deputy determined from tracks that a mountain lion had killed Grayson. He says a neighbor spotted a mountain lion feeding on the llama carcass in his yard Monday and that the sheriff's office advised him to shoot the big cat.
Centrella says he feels bad about shooting the lion but was concerned that it had gotten a taste for the meat.
State officials say Centrella was within his rights to shoot the cat.
Alta is near the Wyoming-Idaho border.