John Stumpf, Chairman and CEO of Wells Fargo, has testified twice in front of Congress that he and other senior managers only realized in 2013 that they had a big problem on their hands - 2 years after the bank had started firing people over the issue.

Yet, in 2005, the year Stumpf became president of Wells Fargo, Julie Tishkoff - then an administrative assistant at the bank - wrote to the company’s HR Department about what she had seen: employees opening sham accounts, forging customer signatures and sending out unsolicited credit cards.

She kept complaining for 4 years, and she was not alone. For years similar or identical complaints from Wells Fargo workers flowed in to the bank’s internal ethics hotline, its HR Department, and individual managers and supervisors. In at least 2 cases in 2011, employees wrote letters directly to Mr. Stumpf - who became the company’s CEO in 2007, and its Board Chairman in 2010 - to describe the illegal activities they had witnessed.

And, during last month's House Financial Services Committee hearing, Maxine Waters (Dem-CA) pointed to court filings from 2008 from employees who tried to blow whistles, and to a Wells Fargo sales quality manual that was updated in 2007 - just months after Mr. Stumpf became CEO, and with his executive guidance - to remind employees that they needed to obtain a customer’s consent before opening an account.

All this prompts the question being asked by regulators, lawmakers, current and former employees, and others:  How was it that this drumbeat of complaints did not set off loud alarm bells earlier? And why have the brunt of the firings fallen on low-level workers, not on the managers and executives who shaped the company’s aggressive sales culture?

FOR THE RECORD, Ms. Tishkoff was fired in 2009. At least 2 of her supervisors were aware of her complaints and ignored them, according to a wrongful termination lawsuit she filed against Wells Fargo in 2011. Those supervisors remain with the bank and are now regional presidents, responsible for overseeing thousands of workers at hundreds of branches.