Sources of British special services have reported that the Russian secret services threatened to hurt the families of chiefs of the Wagner Private Military Company (PMC) before Yevgeny Prigozhin, the owner and leader of the Wagner PMC, stopped his offensive on Moscow.
There was a report floating around that this was in the wheels for longer, so the attack on Wagner was possibly a preemptive strike. https://www.independent.co.uk/news/world/americas/us-politics/russia-coup-wagner-putin-intelligence-b2363901.html#