IRVING, Texas (CBSDFW.COM) – Internal documents obtained by CBS11 raise safety concerns about the construction of the Irving entertainment development, Toyota Music Factory.

CBS11 has obtained a letter sent just last week from the Dallas County District Attorney Office to Irving’s mayor and city council.

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The letter cites allegations of fraud surrounding the building permits obtained during the construction of the Toyota Music Factory and says the DA’s office is reaching out to other agencies to “gauge interest in conducting an investigation.”

CBS11 obtained emails between the developer of the Toyota Music Factory called The ARK Group and contractors.

They show what the head of an Irving taxpayers group calls a reckless and possibly unsafe effort to meet a February deadlines for completion.

Chris Allen of Irving Taxpayers Matter, has photos he obtained from contractors that he says show significant construction work going on after the developer obtained certificates of occupancy.

That’s despite city code which says no physical changes are supposed to take place after a business obtains a certificate of occupancy.

Emails between The ARK Group and construction companies reveal a frantic effort to meet the February deadline or lose $44 million in its agreement with the City of Irving.

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Allen says to do that bars and restaurants in the Big Beat Dallas section had temporary equipment installed to pass inspections which, if true, is illegal.

“At bare minimum there was negligence and we believe now that all the digging that we done that someone could make the conclusion or opinion that there was fraud,” said Allen.

Some city leaders are calling for an investigation and again the Dallas County DA’s Office is gauging interest in that.

The ARK Group denies it authorized the invoices showing the purchase of temporary equipment to pass inspections. The developer also says emails suggesting it was try to fool inspectors is being misinterpreted and not suggesting anything illegal.

The ARK Group is threatening legal action if the city doesn’t pay the $44 million the developer wants for completing the project.

A vote on that by the city council could take place in the next few weeks.

The Toyota Music Factory issued this statement:

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“The construction allegations by Billy Bob Barnett’s group are false and without merit. This is another attempt to blame others for the latest addition to a long list of Mr. Barnett’s business failures. Given the large amount of construction generated by the $200 million project, the City of Irving hired a full-time employee to monitor entertainment center construction, and inspectors visited regularly. City officials were provided unfettered access insuring adherence to all building code requirements.”