MEXICO CITY -- Even as outgoing President Felipe Calderon began the process of turning over his office to his successor with a midnight ceremony in Mexico City’s massive National Palace, his administration was working into the wee hours to hand a jackpot to two of Mexico’s most controversial casino operators.

As Calderon presented incoming President Enrique Pena Nieto with a green-white-and-red Mexican flag, regulators a few blocks away approved a slew of new permits, acting first at 11:58 p.m. on Nov. 30 – ka-ching! – and again at 3:16 a.m. Dec. 1 – ka-ching! In all, the two operators won permits for 94 new gaming establishments. Calderon’s term officially ended at 10 a.m. Dec. 1.

The action redefined the contours of the gaming industry in Mexico and is likely go down in history as a stain on 12 years of rule by the National Action Party, which promise to end 71 years of corrupt rule by the Institutional Revolutionary Party. That pledge, however, foundered on the PAN’s messy relationship with dozens of illegal gaming halls that were created during its reign.

Calderon’s predecessor, fellow PAN member Vicente Fox, oversaw a government that reopened the doors to the gaming industry and, in an echo of history, issued hundreds of casino permits in its final months.

The legality of the Calderon government’s last-minute giveaway of casino permits has been challenged by a judge in the northern Mexican state of Nuevo Leon, who ordered them annulled.

But the permits are only one element of an unfolding scandal that is centered in the gaming and lotteries bureau of the Interior Secretariat, Mexico’s most powerful ministry.

Darkening the clouds over the casino regulators are allegations from a 46-year-old corporate lawyer who was once married to a senior Interior Secretariat official. Among her allegations is that she witnessed Calderon’s personal secretary, Roberto Gil Zuarth, accept a backpack with $800,000 to help smooth over opposition to opening a casino in Queretaro, a prosperous city north of the capital.

Talia Vazquez Alatorre also claims she was a victim of a brutal gang rape led by her then-husband, who is now in prison.

In her crusade for vengeance, she has spilled endless details of the allegedly crooked inner workings of the gaming and lotteries bureau. Seated in an airy office in southern Mexico City, she broke down several times over two lengthy interviews in which she detailed how her ex-husband and two other key former Interior officials left government and dove into the gaming business, falsifying backdated documents with official seals in order to commandeer rival casinos as well as to operate casinos of their own.

Gil Zuarth, who is now a senator and head of the PAN faction in the upper chamber, reacted angrily, saying he would file a defamation suit against Vazquez.

“I have never seen her, I’ve never been to her house . . . nor much less received money from these people or those linked to them,” Gil Zuarth told Mexico City’s MVS Radio on Jan. 9.

Calderon, who this month began a yearlong fellowship at Harvard’s John F. Kennedy School of Government, could not be reached for comment through the university

Casinos operate in a murky legal environment in Mexico. A 1947 law bans gambling. Fox, who came to office in 2000, vowed – and failed – to overturn the ban. Instead, he issued rules that allowed sports betting and bingo parlors. Pushing the rules further, casinos popped up with electronic poker and blackjack machines, and even roulette, and poker and blackjack tables with dealers.