Its been confirmed that the West has high level agents in both the Russian FSB and military version the GRU. I mean very high, like Cabinet level.
Nobody knows who it is though for obvious reasons, but certain leaks could only be known by Putin's inner circle... Such the exact locations of the Chechen Battalion in Ukraine and all the assassination attempts they were ordered to carry out to kill Zelensky, including precise details and timing of the operations, which all ended in failure.
Double agent?