Thomas Borgen resigned in September after an internal investigation found that some 200 billion euros ($224 billion) that had flowed through the bank's accounts from 2007 to 2015 was suspicious in nature.
Borgen's lawyer, Peter Schradieck, on Tuesday told the Boersen newspaper that investigators searched Borgen's home on March 12. That led to preliminary charges, a step short of formal charges. The nature of the charges was not disclosed, which is possible in the Danish legal system.
In November, Denmark's top prosecution authority filed preliminary charges against the bank for "violation of the laws on money laundering." The prosecutors couldn't immediately be reached for comment.