[1] On August 31, 1924, Pep was sent to the Eastern State Penitentiary where he received inmate number C-2559 and had his mugshot and paw prints taken.

Governor Pinchot and his wife Cornelia adamantly denied Pep's murder accusation, calling it a "slanderous and unjustified attack on his reputation" and a "wretched tale."

[2] Pep joined the Pinchot family at Grey Towers residence in Milford, Pennsylvania, during the governor's first term.

"[6] Pep was described by Pinchot in a July 1924 letter as "about a year and a half old, exceedingly friendly and good-natured, rather unusually intelligent, and very quiet",[8][5] though he chewed on the cushions of the sofa that sat on the front porch.

[9] Pinchot also described feeling "over-dogged" after receiving a new lot of puppies, and believed Pep would have more space to exercise at Eastern State Penitentiary.

He was received in "due and ancient form",[6] and on August 31 was given the inmate number C-2559, had his mugshot and paw prints taken,[12] and was entered into the official prison ledger.

[14] In response, Pinchot emphatically expressed that Pep had not killed any cats nor received a criminal life sentence, and instead was there so "the lot of the prisoners would be lightened".

"[3][16] The governor made a statement: Some newspaperman drawing strictly and solely on his imagination, wrote a story to the effect that the dog had been condemned to prison because he killed a cat.

"[17] In a January 1926 New York Times article she denied that Pep had ever killed a thing and stated, "I am told he is a ‘model prisoner.’ But he is not a prisoner.

The Boston Daily Globe published an article on December 26, 1925, with a photograph of Pep sitting in front of a radio microphone while surrounded by prison guards.

A 1935 newspaper article related that Pep had grown "too fat and unwieldy and ancient for active prison service" and was "allowed to spend the rest of his days at the home of a retired guard who begged leave to care for him in his old age.

[26] The Eastern State Penitentiary, later converted to a museum, has a placard for Pep as one of the "notable inmates" and sells stuffed animals of the dog in its shop.