The Geneva prosecutors' office said in a statement that the criminal investigation concerned "aggravated money laundering."
"Chief prosecutor Yves Bertossa and members of the financial police conducted a search in the morning of Feb. 27 at the premises of a company owned by Aleksander Yanukovych," prosecutors said. "Documents were seized," they added, noting that no further details of the investigation would be provided.
Switzerland has been at pains to prevent foreign leaders from using the country's secretive banks as places to hide and launder ill-gotten funds.
In recent years the Alpine nation has frozen accounts linked to former members of the deposed governments in Egypt, Tunisia and Libya.
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