(State House News Service) -- The mayor of Revere is asking the state inspector general and the attorney general to investigate the sale of MBTA land to a subsidiary of Wynn Resorts, which is seeking to build a casino in Everett.

Gov. Charlie Baker said Thursday his administration is looking into the issue, while a Wynn spokesman declined comment.

In a letter Wednesday to Inspector General Glenn Cunha, Revere Mayor Daniel Rizzo said the MBTA and Wynn knowingly closed on the land transaction in late February before the completion of a review under the Massachusetts Environmental Policy Act (MEPA). Rizzo sent a similar letter on Thursday to Attorney General Maura Healey.

Rizzo, who backed an unsuccessful rival effort to build a casino at former Suffolk Downs racetrack in neighboring East Boston, wrote that the MEPA office has confirmed the MBTA's conveyance of the land to Wynn was "illegal."

MEPA Director Deirdre Buckley wrote a March 23 email to Energy and Environmental Affairs Secretary Matthew Beaton, transportation officials and a Wynn representative after a review of documents related to the land transfer.

"Pleased by advised that, based on the information provided, it appears that the Agency Action was taken without complying with the MEPA Statute or its implementing regulations," she wrote. "The Land Transfer was closed... prior to the completion of the MEPA review process and the conveyance documents do not contain sufficient provisions to ensure compliance with MEPA."

She added that the MBTA "has indicated that the execution of the Land Transfer prior to the completion of MEPA review was inadvertent and, therefore, did not include sufficient provisions to address compliance with MEPA."

A copy of the email was provided by Rizzo's office.

Rizzo, in his five-page letter to Cunha, also faulted the state Gaming Commission, saying the agency acted as an "advocate" of the Wynn proposal instead of as a regulator. Rizzo and Boston Mayor Marty Walsh filed lawsuits against the commission after regulators awarded the eastern Massachusetts casino license to Wynn.

According to a Gaming Commission spokeswoman, the land transaction surfaced as a topic during Thursday's commission meeting.

Commissioner James McHugh, who served as chair of the discussions during the awarding of the eastern Massachusetts license last year, said the environmental review process "needs to run its course," according to the spokeswoman, Elaine Driscoll.

"The conclusion of that process is up to the Secretary of Energy and Environmental Affairs," she said in an email. "The Commission will then take a look at those findings and will then follow up with its own review and its own findings. Until that thorough process happens, not a single shovel can go in the ground."

Baker on Thursday also pointed to the MEPA review process. "I think in the end, the MEPA process is going to determine the forward progress on this particular project," he said. "I think the issue that was raised by the folks at environmental affairs is a legitimate one and it's one we're looking into."

On March 3, Wynn Resorts reported it closed on a purchase of MBTA land for $6 million. The 1.75-acre piece is next to the 33-acre site where Wynn plans to build a $1.6 billion casino off Route 99.

"After an extended period of public process and due diligence, we're checking off the boxes and hitting the milestones we need to hit," Robert DeSalvio, president of Wynn Everett, said in a statement at the time. "Right now, there are teams of people in Massachusetts and Las Vegas working around the clock to make sure that permitting, design and planning continue to progress smoothly and building can start as soon as possible."

The purchase of the land was aimed at creating access to the casino through Everett and avoiding access to the casino crossing into Boston city limits.

Citing pending litigation against the state Gaming Commission, a spokeswoman for Mayor Walsh declined comment on Rizzo's letters.

In his letter to Cunha, Rizzo said he is asking for the inspector general's intervention "because I fear any purported cure to this illegal transaction advanced by the perpetrators (the MBTA and Wynn) will fail to mitigate the harm" caused to Suffolk Downs and others involved in the casino licensing process.