Meanwhile on the other side of the country civilians are also being killed and Russian propaganda is working on new excuses:
https://russian.rt.com/ussr/news/978134-mariupol-likvidaciya-dezertiryBC Poccии ликвидиpoвaли 93 yкpaинcкиx дeзepтиpa, кoтopыe бeжaли из Mapиyпoля в гpaждaнcкoй oдeждe, зaявил нaчaльник Haциoнaльнoгo цeнтpa yпpaвлeния oбopoнoй Poccии гeнepaл-пoлкoвник Mиxaил Mизинцeв.
The Russian Armed Forces liquidated 93 Ukrainian deserters who fled from Mariupol in civilian clothes, said Colonel-General Mikhail Mizintsev, head of the Russian National Defense Control Center.
Not sure if they had the supposed deserters in custody, i.e. they executed prisoners of war, or they just shot at civilians from a distance, but either case sounds like an admission of a war crime.
Do they say deserters? That is effectively killing civilians, as they do not have weapons and seem to have given up the army? The only case in which they could potentially be executed is if they were still combatants without uniform (AKA spies / saboteurs) and it would require trial.
What acts are war crimes?
War crimes are defined by the Geneva Conventions, the precedents of the Nuremberg Tribunals, an older area of law referred to as the Laws and Customs of War, and, in the case of the former Yugoslavia, the statutes of the International Criminal Tribunal in The Hague (ICTY).
War crimes fall into three groups - or four if you include genocide.
Crimes against peace
planning, preparation, initiation or waging of a war of aggression, or a war in violation of international treaties, agreements or assurances
participation in a common plan or conspiracy for the accomplishment of any of the above
War crimes
Violations of the laws or customs of war, including:
Atrocities or offences against persons or property, constituting violations of the laws or customs of war
murder, ill treatment or deportation to slave labour or for any other purpose of the civilian population in occupied territory
murder or ill treatment of prisoners of war or persons on the seas
killing of hostages
torture or inhuman treatment, including biological experiments
plunder of public or private property
wanton destruction of cities, towns or villages
devastation not justified by military necessity
Crimes against humanity
Atrocities and offences committed against any civilian population, before or during the war, including:
murder
extermination
enslavement
deportation
mass systematic rape and sexual enslavement in a time of war
other inhumane acts
persecutions on political, racial or religious grounds in execution of or in connection with any crime within the jurisdiction of the Tribunal, whether or not in violation of the domestic law of the country where perpetrated
Responsibility for such crimes
Leaders, organisers, instigators and accomplices participating in the formulation or execution of a common plan or conspiracy to commit any of the crimes above are criminally responsible for everything done by anyone in carrying out such a plan.
Superior orders
The fact that a person was obeying an order of his Government or of a superior does not free him from responsibility, but can be considered and may reduce the appropriate punishment.
Of these, crimes against peace are quite clear, also these three war crimes are certain:
plunder of public or private property
wanton destruction of cities, towns or villages
devastation not justified by military necessity
On crimes against humanity, I think that "murder" is certain, "deportation" seems likely, "other inhuman acts" quite likely.
I do not think there is really a way to talk Putin's way out of these - I mean, credible way.