The City of Denver has suspended Mortenson from bidding on construction projects until a board can review the company's qualifications.

Mortenson was one of the companies bidding to be the contractor for the Colorado Convention Center expansion project, which was put on hold Dec. 11 after the city determined the process was tainted from what Mayor Michael Hancock called "a significant breach of the public trust and a willful violation of a competitive bidding process." The city ended its $9 million contract with the Trammell Crow Company, which was acting as the expansion project manager.

The Denver Public Works Department provided 9NEWS with emails between Trammell Crow and Mortenson that describe why the city thinks there was funny business going on.

RELATED: Mayor asks DA to investigate ‘misconduct’ in Colorado Convention Center expansion contracts

"We have sufficient evidence to indicate that there has been a level of collusion on the Convention Center expansion project," said Denver Public Works Director Eulois Cleckley. "We had a company that not only received the answers to the test, but actually, wrote the answers to the test, and so thereby creating a competitive advantage over the other bidders."

To understand the email exchanges, you need to understand the players. There's Trammell Crow, the company in charge of the Colorado Convention Center expansion project. There's Mike Sullivan, Senior Vice President of Trammell Crow. And there's Mortenson, a company bidding to be the contractor.

Food flirting

In a series of emails between Sullivan at Trammell Crow and Mortenson sent in May of this year, Sullivan and Mortenson joke about going out for drinks when Mortenson is awarded the contract.

"…let me know which of these items you need more info (such as drawing, sketches, or whatever in order to price," wrote Sullivan to Mortenson. "And I am serious about wanting to take you and Sean out for a nice dinner, where we can eat and drink our faces of. I would like to do that to say thanks."

Days later, Sullivan sent another email to Mortenson asking to take them out for "some nice food and drinks."

Mortenson replied: "I can think of a day that would be awesome… [smiley face] The day we get this job!"

"Nope," Sullivan replied via email. "That's the day YOU guys can take ME out! Ha ha!!"

Sharing documents

On June 29, the city forwarded Trammell Crow information that described the workforce development requirements it wanted a winning bidder to meet. The city specifically asked Trammell Crow not to share the information.

Less than a week later, Sullivan had forward the workforce development requirements to Mortenson, adding, "FYI As always, keep this quiet."

On July 20, the City of Denver then emailed Trammell Crow a proposed contract for the Colorado Convention Center expansion project. Three days later, Sullivan forwarded the contract to Mortenson.

Then on July 25, when the city forwarded a "new draft contract" to Trammell Crow, Sullivan forwarded it to Mortenson. 

What the city calls "proof" of collusion

A month earlier, on June 26, Mortenson wrote Sullivan an email asking, "…were you able to get any language into the RFQ stating that the City doesn't want any 'teams' to be created to maximize the WMBE [sic] opportunities with the prime contractors? This is another element that would 'shutdown' Turner and their plans with Gilmore."

The city told 9NEWS this email is proof Mortenson and Trammell Crow "exchanged information that was specifically designed to eliminated Turner Construction as a bidder. Both Turner an Gilmore are construction companies.

An RFQ is a "request for qualifications" and it refers to the qualifications needed to even be in the running to be selected for a city project. 

"WMBE" is really "MWBE," which stands for Minority and Women-Owned Business Enterprise. City projects come with a specific percentage of work that must be completed by a minority or woman-owned business.

The city was drafting specific requirements for minority and women-owned businesses to be included in the expansion project.

"What we identified was that there was direct communications through one bidder to try to craft language that would eliminate future bidders that had included a minority and woman-owned business to be eligible, or to be in the position to bid on that project," Public Works Director Cleckley told 9NEWS.

"Live scenario" questions

A series of emails from August and November between the companies show conversations around "live scenario" questions. According to the city, "Mortenson and Trammell Crow worked together to draft the confidential 'live scenario' questions for use by the City during the interview of the final three bidders, one of which was Mortenson."

"Live scenario" questions would be unexpected scenarios that would be asked during the interview process to see how a team would respond to unexpected circumstances.

An email from Aug. 28 shows Mortenson emailing Sullivan three questions. An hour later, Sullivan emails those three questions, with two others, to the city. It's unclear from the emails if Mortenson drafted the questions or just saw them in an email. In a Nov. 8 email, Sullivan forwarded a question to Mortenson that was similar to a previous question Mortenson saw in the August email, but with slightly different wording.

"The total summary of all of these emails is quite concerning," said Cleckley.

The fallout and response

Trammell Crow has hired Hogan Lovells, a prominent Denver law firm.

According to an attorney with the law firm, Hogan Lovells is currently doing its own internal investigation. He said that's how the city ended up with the emails that 9NEWS now has.

The city said it received the emails because its contract with Trammell Crow allows for that since any work produced from the convention center expansion project would be considered city work product.

On Monday morning, Trammell Crow emailed 9NEWS the following statement from Senior Managing Director Bill Mosher:

“As we have said previously, we are continuing to cooperate fully with the City and the District Attorney. We are pursuing our own thorough internal investigation with the assistance of Hogan Lovells, one of the nation’s top law firms. The emails released by the City were voluntarily turned over to the City by Trammell Crow Company as part of our ongoing investigation and cooperation.

The emails of our former employee Mike Sullivan’s interactions with Mortenson reflect statements and actions that were not authorized by Trammell Crow Company in any way. Mr. Sullivan’s communications were improper, contrary to our values and longstanding business practices, and the reason we terminated his employment."

Mortenson has hired Denver-based Aiello Public Relations and Marketing. Wendy Aiello emailed the following statement on behalf of Mortenson Senior Vice President Maja Rosenquist:

"Mortenson is in contact and fully cooperating with the District Attorney regarding this matter. We have given them our assurance that we will not be providing further statements while they are conducting their investigation. We take this matter very seriously. We have conducted a thorough internal investigation, and commit to cooperating with the City to the greatest extent possible."

Mortenson has had prequalification status to bid on specific city projects, like the Convention Center expansion project.

"We are suspending their ability to bid on future projects," Cleckley told 9NEWS.

Until the prequalification board reviews Mortenson, it won't be allowed to bid on a number of projects involving civil, excavation, piped water and sewer, concrete, sidewalk, curb, or gutter work, among others.