The brother and best man of Bernard Kerik, the former New York City police commissioner, were not the only well-connected New Yorkers working for a New Jersey contracting company fighting accusations it had ties to the mob.

Around the time regulators from at least three New York City agencies worked to ban Interstate Industrial Corporation from city contracts in 1999 and 2000 for its associations with members of the Gambino crime family, three former high-ranking officials in the Giuliani administration or their companies were hired as employees or consultants by the firm, according to documents obtained by The New York Sun and the company’s chairman, Frank DiTommaso.

Those who were hired include a former deputy mayor and Giuliani anti-mob czar, Randy Mastro, and a former commissioner of consumer affairs, Angelo Aponte. Property records show that Mr. Aponte also served as a director of a separate company registered to the same address as Interstate at the time. Also hired was a security company headed by William Bratton, who had been Mr. Giuliani’s police commissioner and now holds that job in Los Angeles.

In New Jersey, where Interstate is fighting to retain the right to do business with Atlantic City casinos, a former Republican assemblyman and director of gaming enforcement, Frank Catania, is on the payroll, according to Mr. DiTommaso.

Interstate, a firm that does construction and waste hauling, has done more than $100 million of business with New York City.

It has also contributed thousands of dollars to the campaigns of prominent local politicians in New York City and New Jersey since the allegations of mob ties first arose. At least one of those politicians, Rep. Vito Fossella, Republican of Staten Island, has worked to clear Interstate’s name.

Court documents, interviews, and campaign-finance records paint a revealing picture of the close and sometimes murky ties among city contractors, local politicians, regulators, mobsters, and money in politics in the tristate area.

Interstate has been in the headlines recently for its role in the scandals embroiling Mr. Kerik, who withdrew his name December 10 from consideration for secretary of homeland security amid growing controversy, and who resigned yesterday from Giuliani Partners. Since then, new disclosures have surfaced about Mr. Kerik’s connections to Interstate, the firm in Clifton, N.J., that hired Mr. Kerik’s brother Don and longtime friend Lawrence Ray in the late 1990s.

Mr. DiTommaso says Mr. Ray was hired because he was “very well-respected in the law enforcement community.” Interstate hired Don Kerik at the suggestion of Mr. Ray, after Mr. DiTommaso learned he had experience running a transfer station. Mr. Ray was eventually indicted for his role in an alleged mob-run pump-and-dump stock scheme, and Mr. DiTommaso let him go. He was later convicted. According to testimony in New Jersey, however, Mr. Ray, who was best man at Mr. Kerik’s 1998 wedding and helped pay for it, continued to stay in contact with Interstate, even borrowing $350,000 from the company – a loan Mr. Ray never repaid.

In recent months, Interstate has not been shy about its former association with Mr. Kerik’s friends or Mr. Kerik himself. Mr. DiTommaso invoked the former police commissioner’s name at hearings before the New Jersey Gaming Commission in an effort to clear his company’s name and beat back the mob allegations, documents show.

New Jersey regulators first raised the allegations of mob ties while conducting background checks to determine the suitability of Interstate to do business with casinos in Atlantic City. The allegations, which Mr. DiTommaso said are based on lies from two questionable informants, created a “snowball effect.”

Several New York City agencies subsequently barred the company from doing business with them, citing its association with a wide array of figures associated with the Gambino crime family, including the son-in-law of mob turncoat Sammy “the Bull” Gravano and the grandchildren of slain mob boss Paul Castellano.

The New Jersey Gaming Commission approved Interstate’s permit last month, after the longest hearing in its history. The state attorney general’s Division of Gaming Enforcement then filed a scathing appeal, which is pending.

“In the entire history of casino regulation in New Jersey, this case stands alone as one in which the Commission granted licenses to applicants who had previously been deemed unsuitable by government agencies in another jurisdiction because of their organized crime connections,” the appeal states.

Fresh allegations have emerged in recent weeks. At the trial of Peter Gotti, two witnesses testified that Interstate paid protection money to the Gambinos and had long provided a regular source of income to the De-Cavalcante organized-crime family at Staten Island.

In an interview yesterday with the Sun, Interstate’s chairman, Mr. DiTom maso, vehemently denied any links to the mob and said his campaign contributions were unrelated to the allegations. But he acknowledged turning to former politicians and city officials to help him clear his name.

“These associations were unknown and unavoidable,” he said. “Even if they had bad reputations, there was nothing improper done with the business deals. We did business with local contractors licensed by the city. Who knew they were bad guys?”

Mr. DiTommaso said he has spent close to $2 million since 1998 to avoid dealings with disreputable contractors and to conduct background checks of potential associates. Much of that money went to former public officials in both New York City and New Jersey. In addition to hiring a consulting firm run by Mr. Bratton and another firm run by former New York Police Department drug enforcement detectives, Mr. DiTommaso hired Mr. Mastro, the former deputy mayor, to clean up the company. Mr. Mastro played a key role in the Giuliani administration’s efforts to weed out mob-connected businesses.

“Who has better credentials than Randy Mastro, who wrote the regulations?” Mr. DiTommaso said.

The former consumer affairs commissioner, Mr. Aponte, appears to have enjoyed the closest relationship with Interstate. In addition to signing on as an executive with Interstate, property records examined by the Sun list him as a director of a now-defunct finance company operated out of the same building as Interstate and co-owned by Mr. DiTommaso.

He also appears to have contributed to many of the same politicians as did Mr. DiTommaso during the time Interstate sought unsuccessfully to retain its lucrative city contracts, campaign finance records show.

In July and December 1999, Mr. Aponte, Mr. DiTommaso, family members, and employees associated with Interstate contributed more than $60,000 to the mayoral campaign of the New York City comptroller, Alan Hevesi – who now is state comptroller. Mr. Hevesi eventually returned all the donations – and he also rejected at least one city contract with Interstate, citing their associations with mobsters.

“It worked just exactly the way it was supposed to,” a Hevesi spokesman, David Neustadt, said. “The campaign raises money from those willing to contribute. They have no idea who does business with the city. When it was discovered, the money was returned. And Hevesi rejected a contract after the company gave money. It had no influence.”

For his part, Mr. DiTommaso says he decided to hold a fund-raising event for Mr. Hevesi after meeting him through the company treasurer, Earle Tockman, who was an old friend of the comptroller’s.

“I’m a community-minded person,” Mr. DiTommaso said. “If I see a politician or civil servant who I believe is going to do a good job for the community, I’ll support him.”

Mr. Fossella, the Staten Island congressman, received more than $5,000 in campaign contributions from members of the DiTommaso family. Mr. Aponte and his wife, Linda, also contributed about $1,000.

In a document dated August 25, 1999, the Staten Island Republican wrote a “letter of character” to the New Jersey State Gaming Commission, praising Interstate owners Frank and Peter DiTommaso and urging New Jersey to approve Interstate’s application to do business with casinos in Atlantic City.

“I have known Frank and Peter DiTommaso for over twenty years,” Mr. Fossella wrote. “They are men of impeccable integrity and honesty and have given much to the community of Staten Island.”

Mr. Fossella’s spokesman dismissed the idea of a link between the contributions and the letter as ludicrous.

“All we know of them is that they are reputable and hardworking individuals,” the spokesman, Craig Donner, said yesterday. “Vito has known the family for more than 20 years.”

Efforts to reach Mr. Aponte, Mr. Bratton, and Mr. Mastro for comment last night were unsuccessful.

Mr. DiTommaso and his employees have also contributed to a number of New Jersey state assembly and congressional campaigns. Among the recipients is William Gormley, a state senator from Atlantic City who until recently headed the powerful Judiciary Committee and could have influence with the five-member Casino Control Board. Members of the board are appointed to staggered terms by the governor, in consultation with the Senate majority leader. New Jersey political observers said Mr. Gormley, as representative of Atlantic City, would almost certainly have been consulted when he held his powerful post.

In the end, the ability of Mr. DiTommaso’s company to do pass muster with regulators in New York and New Jersey may depend on his success in avoiding mob-connected contractors, a course he said he is committed to.

“Remember, these allegations have not yet been proven to be true,” he said. “At the end of all the work, the New Jersey Gaming Authority had not one issue with our performance.”