Tuesday is looking like D-Day for

Security Trust

, a Phoenix-based trust bank that played a pivotal role in the mutual fund trading scandal.

Regulators and prosecutors are set to bring a combination of civil and criminal charges against the bank and several former top executives, people familiar the investigation said. Security Trust allegedly helped

Canary Capital Partners

and other hedge funds engage in illegal late trading of mutual fund shares.

Sources said the series of charges to be filed simultaneously by New York Attorney General Eliot Spitzer and the

Securities and Exchange Commission

could force the bank to shut its doors, or severely cut back its operations. In addition, bank regulators at the Office of the Comptroller of the Currency are set to file administrative charges against Security Trust, which serves as a custodian and trustee for more than 2,500 retirement plans with $13 billion in assets.

Two former top executives at Security Trust, Grant Seeger and Bill Kenyon, also are likely to face criminal charges, said people familiar with the investigation.

Lawyers for Seeger, the company's former chief executive, and Kenyon, the company's former president, declined to comment.

Nancy Murphy, a spokeswoman for Security Trust, said Monday afternoon that the company is "not aware of any charges.''

Last month, sources said, the OCC forced Security Trust to come up with an additional capital infusion to maintain the stability of the bank, as the mutual fund trading scandal began to unfold.

Security Trust has been linked to the mutual fund trading scandal from the start.

Spitzer's office alleged in September that Security Trust assisted several hedge funds, including Canary, in engaging in improper trading in shares of various mutual funds. In reaching a $40 million settlement with Canary, Spitzer's office alleged that Security Trust allowed the hedge fund to make improper trades in shares of hundreds of mutual funds. In exchange, Security Trust allegedly received a cut of Canary's illicit profits.

In the weeks since the scandal broke, Security Trust has laid off or fired more than two dozen employees.