An investigation continues two months after a Pittsburgh Public Schools board member said his signature was forged on an official letter in support of bringing Amazon’s second headquarters to the city.

The firm hired to determine who signed Kevin Carter’s name on the document won’t comment on the case and board member Kevin Carter isn’t talking either.

Previously, Carter claimed he never saw or signed the letter. He said he wanted whoever signed his name to be fired.

The district was asked to submit a letter of support as one of the city’s three taxing bodies. At the time the letter was dated, Carter chaired the business and finance committee. A signature appears on the letter above his name alongside that of Superintendent Anthony Hamlet.

Shortly after Carter posted his claim on Facebook, the district hired Monaca-based Corporate Security and Investigations. CEO Bill Hickman said there could be more information in the coming weeks.

District Solicitor Ira Weiss said he was interviewed by the company. But, he doesn’t know when the investigation will conclude.

Weiss told board members in a November email that the letter did not make any commitments to Amazon.

“The letter was signed by Dr. Hamlet, and I met with Mr. Carter in my office,” Weiss wrote to board members. “I emphasized the board was not committed to anything other than discussing projects as they came forward.”