These energy company oligarchs were unable to make payments due to the sanctions and war disruptions. They couldn't make the payment so they were liquidated mafia style by whoever owned them outside Russia.
or
Putin has declared war on the bad guys, and these were bad guys in league with the CIA. Putin had them liquidated.
or
These energy company oligarchs knew where the bodies were buried, where the money went etc. and were paid by the CIA over the years. Now that their protectors higher up in the FSB were arrested they were implicated. The CIA liquidated them before they could talk.
Scenarios:
These energy company oligarchs were unable to make payments due to the sanctions and war disruptions. They couldn't make the payment so they were liquidated mafia style by whoever owned them outside Russia.
or
Putin has declared war on the bad guys, and these were bad guys in league with the CIA. Putin had them liquidated.
or
These energy company oligarchs knew where the bodies were buried, where the money went etc. and were paid by the CIA over the years. Now that their protectors higher up in the FSB were arrested they were implicated. The CIA liquidated them before they could talk.