I meant the very first post in this thread (Snipers from the SBU, duh). Now I found further confirmation in a Spiegel article from three days ago; from an anonymously interviewed Ukrainian oligarch who fled to Moscow (Note: "ALFA unit" was the inofficial name of the KGB hit teams, inherited by post-Soviet successors):

Post Yanukovych Ukraine Looks to Avoid Past Pitfalls - SPIEGEL ONLINE

Oleg can effortlessly recite the names of section heads responsible for issues pertaining to Russia and Ukraine in the foreign ministries of Western European capitals. He knows them all. He soberly recounts how Europe rebuffed him and his delegation while the Kremlin ratcheted up the economic pressure on Ukraine in recent years. "The EU should have gotten involved," he says.

Then Oleg explains the preparations made by Yanukovych to storm Independence Square, the location of the mass protests that ultimately brought down his government. Oleg says he knows that fighters from the elite ALFA unit were responsible for setting fire to opposition headquarters and that ALFA snipers opened fire on demonstrators from the rooftops of surrounding buildings. "Everything went according to plan. But then Yanukovych suddenly flinched and ordered the offensive to be stopped," Oleg says.

He says that when foreign ministers Frank-Walter Steinmeier, Laurent Fabius and Radoslaw Sikorski spent the night negotiating with Yanukovych on February 20-21, the Ukrainian president's aides were busily preparing his escape. "They packed up suitcases and boxes. In the end, the helicopters were so heavy that they could hardly take off," Oleg says.