The bank has suspended or removed four employees in recent months amid investigations into alleged wrongdoing, which includes attempts to sway federal contracts toward favored companies, people familiar with the matter told the Wall Street Journal.

In one case, an official in the short-term trade finance division, Johnny Gutierrez, was said to have accepted cash in exchange for helping a Florida company get federally-funded financing to export construction equipment to Latin America.

Gutierrez, who people said was escorted out of the agency in April, was part of the Ex-Im Bank’s central functions: providing financing for exports. His lawyer confirmed that he was put on leave after an investigation, but wouldn’t comment on details, according to the report.

Two other employees are accused of improperly awarding contracts to help run the agency, while a third is under investigation for accepting gifts in exchange for helping a company secure financing, sources told the Journal.

The Ex-Im Bank has about 400 employees that help finance export deals for a variety of large corporations, such as Boeing (BA), General Electric (GE) and Caterpillar (CAT). The agency has recently come under pressure by legislators who don’t want to renew the bank’s 80-year-old charter when it expires in September. The internal investigations could complicate an already fraught political environment.

Fred Hochberg, the bank’s chairman and inspector general, is set to testify before a congressional panel Wednesday concerning the Ex-Im Bank’s mission and operations. In recent months, Hochberg has been criss-crossing the country talking up the benefits his agency brings to the U.S. economy in a bid to consolidate support for the Treasury-funded agency.