The Wilson Centre website contains a great deal of valuable and sometimes hard to find information on declassified International History.
Amongst the many documents of interest, you will find 'Vassiliev's Notebooks'. As the name implies, the page has a comprehensive set of notebooks that relate to the activities of the KGB in the early days of the Cold War, it is recommended reading for any researcher or student with a serious interest in the events of the time. As you will read, there are a number of mentions of Pavel Ivanovich Fedosimov in the documents, none of which I could find were dated after Agust 1948.
The files and PDFs can be downloaded or read online in a variety of formats.
I suggest that you read the File Guide first followed by the Concordance and then the various notebooks.
The work that Alexander Vassiliev has put into these documents is astonishing, the detail and perspective will amaze you. I heartily recommend these notes and sincerely congratulate Alexander on these significant documents which are of enormous historical value.