"'Pep, The Cat-Murdering Dog' was a black Labrador Retriever admitted to Eastern State Penitentiary on August 12, 1924."

"Prison folklore tells us that Pennsylvania Governor Gifford Pinchot used his executive powers to sentence Pep to Life Without Parole for killing his wife’s cherished cat. Prison records support this story..."



That's the story at Mugshots.com. This might be more accurate.