And Mr. Manafort’s presence remains elsewhere here in the capital, where government investigators examining secret records have found his name, as well as companies he sought business with, as they try to untangle a corrupt network they say was used to loot Ukrainian assets and influence elections during the administration of Mr. Manafort’s main client, former President Viktor F. Yanukovych.

Handwritten ledgers show $12.7 million in undisclosed cash payments designated for Mr. Manafort from Mr. Yanukovych’s pro-Russian political party from 2007 to 2012, according to Ukraine’s newly formed National Anti-Corruption Bureau. Investigators assert that the disbursements were part of an illegal off-the-books system whose recipients also included election officials.

In addition, criminal prosecutors are investigating a group of offshore shell companies that helped members of Mr. Yanukovych’s inner circle finance their lavish lifestyles, including a palatial presidential residence with a private zoo, golf course and tennis court. Among the hundreds of murky transactions these companies engaged in was an $18 million deal to sell Ukrainian cable television assets to a partnership put together by Mr. Manafort and a Russian oligarch, Oleg Deripaska, a close ally of President Vladimir V. Putin.