After a lengthy investigation, Wayzata-based TCF Financial Corp. was hit with a $10 million fine for gaps in the way it monitors suspicious bank transactions, according to the Star Tribune.

Under the Bank Secrecy Act, regulators have increased their efforts to monitor financial institutions to make sure illegal money is not flowing through them. The crackdown is to prevent money laundering and potential financing for terrorists and drug dealers.

Regulators said TCF mishandled or was tardy in filing mandatory reports.

TCF spokesman Jason Korstange said the bank did a "very, very thorough examination of all our accounts," and did not find any evidence of terrorist activities. TCF said it overhauled its program for complying with the Bank Secrecy Act. In addition to paying the fine, TCF agreed to refile reports and increase employee training. The bank has also implemented a new software program to flag unusual transactions.

With $19 billion in assets and 1 million customers with checking accounts, TCF is Minnesota's third-largest bank.