The man in the backyard

Killed in the courtyard Grigory Mikhailovich Yushkov was considered dead during the Second World War. In the same years, under strange circumstances, the partisan detachment and the entire urban underground were destroyed. They were betrayed by a man named "Centaur", which was never found. What is the motive for Yushkov’s murder and is he not a Centaur? This is to be found out by an investigator from Moscow.