NEW YORK (CBSNewYork) — Call it another legal headache for the Big Apple’s mayor.

One of Bill de Blasio’s opponents has demanded that state and federal prosecutors investigate the mayor’s plan to solicit contributions to pay his mounting legal bills.

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As CBS2 political reporter Marcia Kramer reports, de Blasio already has two grand juries looking at his recent actions and the hefty legal bills that come with it.

But his decision not to pay them — rather to set up a legal defense fund sometime in the future where people who might have business with the city can contribute — is coming under fire.

“How can de Blasio think it’s okay to go into debt with a law firm that frequently does business with the city?” mayoral candidate Paul Massey said. “No ordinary person can get legal services with no plan to pay for them.”

Massey wants to unseat de Blasio — he has the independent party endorsement and is seeking the Republican Party line as well. He sent letters to Manhattan District Attorney Cyrus Vance and US Attorney Preet Bharara demanding an investigation into the mayor’s dealings, questioning whether the legal defense fund violates criminal law, the city charter, or ethics laws.

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“Mayor de Blasio often likes to say that we’re living in a tale of two cities,” Massey said. “He’s right, he believes there’s one set of rules for Bill de Blasio and one set for everybody else.”

When pressed for an explanation, the mayor said “we haven’t even gotten to the point of figuring out how to set up an appropriate entity.”

“We haven’t structured it yet,” he continued. “We’re certainly going to be sensitive to making sure it’s fair.”

“I’m not a millionaire or a billionaire,” he said. “I’m not in a position to do this and pay these bills myself. We’re not asking the taxpayer to pay my bills.”

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The US Attorney’s office refused to comment on Massey’s request, while a spokesperson for District Attorney Vance said “we’ve received the letter and will have no further comment.”