Mitsubishi UFJ Financial Group said it fired an employee who allegedly stole up to 2 billion yen ($13 million) from the safes of about 60 customers.

The theft took place at two Tokyo branches more than 4 1/2 years before it was discovered on Oct. 31, MUFG’s main banking arm said in a statement on Friday. Japan’s largest bank is investigating the incident and consulting with police, the statement said.

The frontline employee was responsible for managing the safes and “took advantage of that position” to open them without permission, the bank said. The market value of the damages was between ¥1 billion and ¥2 billion. The person admitted. to the wrongdoing and was dismissed.

“This act not only undermines the trust and confidence that customers have placed in us, but also shook the very foundation of our business,” MUFG said, adding that there were no similar incidents in other branches.

“The bank is considering and will quickly implement appropriate compensation” for the damage suffered by customers, as well as measures to prevent recurrence, it added.

MUFG is the latest major Japanese financial firm to reveal alleged crimes by core staff. Nomura Holdings said this week that a former employee was charged on suspicion of robbery, attempted murder and arson after allegedly drugging and stealing money from an elderly customer at their home in Hiroshima.