COLUMBUS, Ohio (WCMH) -Even as Mayor Michael Coleman reiterates that he has done nothing wrong, he announced an investigation of a city employee for alleged improprieties.

NBC4 has discovered letters showing the mayor took an active role in helping Dr. Jianhua Li, a Chinese businesswoman who bought the mayor’s home for $520,000 in 2010.

The mayor disputes the price paid for the home was inflated or that it was in exchange for favors.

In more than a thousand pages of documents released by the city today, including emails, letters and other correspondence, NBC4 uncovered official letters from Mayor Coleman to two U.S. Ambassadors to China. He requested expedited visas for Dr. Li to come to Columbus–at a time when she was trying to get a foothold in Columbus for her business.

In an official letter on a letter stamped “OFFICE OF THE MAYOR” to Ambassador Max Baucus, dated June 24^,2014, Mayor Coleman says “Mrs Li… has developed an affinity for our city and is people.” The mayor also points out that “Mrs. Li has inquired into and shown her genuine interest in partnering with The Ohio State University’s Alternative Medicine Research Programs.”

Mayor Coleman asks for an expedited Visa for a 6 month period, from June1, 2014 to December 15, 2014

It wasn’t the only request.

In another official letter, dated September 12, 2013 to then-Ambassador Gary Locke, Mayor Coleman requests another expedited visa for Dr. Li to come to Columbus. He stated Dr. Li’s visit was “to generate new jobs through her prospective investments and future establishments of joint business ventures.”

In a statement released by Coleman’s office, the mayor says he “did not ask any city employee to help Dr. Li beyond that which we routinely do to support economic development in Columbus. We will determine the full extent to which this employee acted beyond the scope of his employment on behalf of Dr. Li, and why.”

Mayor Coleman announced the city is launching an official in to a city employee, confirmed by NBC4 to be Bob Hsieh (Shay), a city development official.

In the documents released Wednesday, emails reveal Hsieh communicating directly with Dr. Li about financial matters, including communications where Hsieh arranged payments for Dr. Li’s bills.

The emails show Hsieh taking care of Dr. Li’s home after she bought it from the mayor, trying to help Dr. Li purchase another home in New Albany.