Last week, Mr. Kernes rushed to calm pro-Russian activists calling for secession, appeared as a mediator at the shootout where Mr. Zhudov was killed and met behind closed doors with representatives of the Organization for Security and Cooperation in Europe, which is tasked with preventing conflict and promoting democracy. (On Saturday, Russia endorsed the deployment of a team of 100 international monitors approved by the O.S.C.E. in places outside Crimea, saying the team had no mandate there.) Yet with the fear of war abating, Mr. Kernes, who has dominated politics here for several years, has resumed his role as one of Kiev’s fiercest critics, accusing top officials of pursuing political retribution and calling the new government tyrannical and illegitimate.

“People ask if I like the new authorities, but I prefer a different question: Does the new government actually like our people, with their demands, their desires, their dreams?” Mr. Kernes said in a recent interview between spoonfuls of raspberry jam in a restaurant at the downtown hotel he owns.

Mr. Kernes, who lives a lavish lifestyle and has been rumored to have ties to organized crime, was accused of murder and kidnapping last week. He denied the accusations and said they were politically motivated attacks from a former political rival, now the country’s interior minister, Arsen B. Avakov.

The Kiev government has also attacked Mr. Kernes’s closest political ally, Mikhail M. Dobkin, the former regional governor and now a presidential candidate, accusing him of “threatening the territorial integrity” of Ukraine.

The charges, which set off tremors through the political establishment here, are fueling disillusionment with the government.

“Here we have an acting president,” Mr. Kernes said, referring to the interim president, Oleksandr V. Turchinov. “In Russia, they have a president. There they don’t have political chaos, and here what do we see? Political chaos.”