Looking for Primary Sources on Stalin's Relationship with Lidiya Pereprygina

A colleague recently brought up Stalin's supposed relationship with a fourteen year old lidiya, and said they had read about it in montefiore's book, they also said that Lidiya spoke about her relationship with Stalin in a diary that is allegedly held within a national/Presidential archive ( I have found nothing of this), and that there was a local police report about the nature of their relationship.

knowing that khruschev had people look into these claims purposely and that he had motive to make up lies about stalin and that some of these claims are based on government documents which could be falsified, I was wondering about the truth of these claims, whether there is any, and what sources the people making these claims use in order to justify it.