The European Court of Human Rights (ECHR) ruled Tuesday that Russian President Vladimir Putin probably approved the assassination of ex-KGB officer Alexander Litvinenko.

Litvinenko died in 2006 due to drinking green tea poisoned with a radioactive isotope Polonium-210 in a London Hotel. Acting as an officer for the FSB security, Litvinenko was a consistent critic of Putin and fled to the UK where he was poisoned upon meeting the defendants. The Kremlin denies any involvement in the assassination of the officer. In response to the ruling, a Kremlin spokesperson called the claims made in the judgment “unsubstantiated.”

The ECHR ruling supports “beyond reasonable doubt” the findings of the 2016 British inquiry that concluded that the intelligence operation to murder Litvinenko in London was probably approved by Putin. Those responsible for the assassination were former KGB bodyguard Andrei Lugovoy and Dmitry Kovtun. The ECHR has also made inferences from Russia’s “state of refusal to disclose any documents relating to the domestic investigation.”

Fifteen years after the murder of Litvinenko, the ECHR has ordered Russia to pay the ex-KGB officer’s wife, Maria, US $117,304 in damages plus $26,389 in costs. A request for punitive damages was rejected by the Strassbourg court.