CEO and President of Wells Fargo & Company Timothy Sloan testifies during a hearing before Senate Banking, Housing and Urban Affairs Committee October 3, 2017 on Capitol Hill in Washington, DC.

The Department of Justice is investigating a banking unit of Wells Fargo after the bank's review found that employees' altering of documents was a more pervasive practice than previously thought, according to The Wall Street Journal on Thursday.

The government's latest examination of potential fraud by Wells Fargo is focused on its wholesale banking unit, the report said, citing people familiar with the situation. The DOJ reportedly has already been looking into sales practices in the bank's wealth management business.

Shares of Wells Fargo fell 1.2 percent in trading.

This revelation follows the discovery that Wells Fargo employees had wrongly changed or added customer information, the report said. Some employees of the wholesale banking division added information such as birthdays and Social Security numbers, according to the report, without asking for customers' consent.

Wells Fargo is already set to pay a $2.09 billion fine to the DOJ for alleged misrepresentation of loan quality, the government announced in August. The fine is for alleged origination and sale of residential mortgage loans that the lender knew contained misstated income information and did not meet the quality that Wells Fargo represented, the DOJ said in its statement.

Read the full report in The Wall Street Journal.