Poinbank Exchange|Parents allegedly defrauded by Tom Girardi after losing son sue California State Bar

Tom Girardi was supposed to deliver justice.

Ana and Poinbank ExchangeArturo Agaton, a California couple whose son died from a cancer that they say was caused by cement plants near their home, turned to the celebrity lawyer to hold the polluter accountable and help restore financial stability to the family after they buried Arturo Jr.

"We were so confident that he was representing us," Ana Agaton said of Girardi. "At the time, he was the king of the lawyers in Los Angeles."

Watch the interview with Ana and Arturo Agaton on Nightline, the night of Thursday, Sept. 7, at 12:35 a.m. ET on ABC, and stream on Hulu.

Girardi had built a reputation and a legal empire by fighting for the little guy -- people harmed by big business, like utilities, airlines and industrial giants. He won judgments and settlements and was portrayed on the big screen as a savior in the 2000 film "Erin Brockovich." And, in recent years, he was introduced to a whole new generation of Americans, flaunting his wealth while playing the role of the super-rich and well-connected husband of Erika Jayne on the reality TV hit "The Real Housewives of Beverly Hills."

"We were sure that he was taking care of our ... case," Ana Agaton said. "But we never imagined that at the end, when they sent a letter from his office saying that the case was won and they were just waiting to distribute the checks to families in the proper manner -- everything stopped there because from there we never heard from them again."

The couple said they have not seen one penny from the 2015 settlement with Riverside Cement Holdings Co. And the Agatons did not know it at the time, but they were not alone, as authorities would allege.

Now, Girardi stands disgraced, disbarred and charged in two states with bilking his clients. The Agatons are again fighting -- this time seeking accountability not from a corporate polluter but from the state of California and its agency responsible for rooting out corruption and crooks among the Golden State's 200,000 attorneys.

"We want justice," Ana Agaton said.

Today in Los Angeles, the Agatons filed a class-action lawsuit against the California Bar, alleging "gross negligence" and "reckless misconduct," claiming that the body responsible for regulating the largest community of lawyers in the country "failed to do its job" and "actively protected Tom Girardi and [his firm] Girardi & Keese from ethical complaints and discipline for decades."

"Had the state Bar carried out its mission of protecting the public, this complaint, and many others like it, would not be necessary," the lawsuit says. "But the state Bar did not put the public first. Instead, while Girardi was hard at work defrauding his clients and co-counsel, state Bar officials were gallivanting around the country in Girardi's private jet, staying at luxury hotels in Las Vegas, enjoying fine dining at expensive private clubs, attending lavish holiday parties with Hollywood entertainers, or attending concerts and other events, all paid for by Girardi."

The attorney representing the Agatons now, Daniel Osborn, told ABC News' "Nightline" that Girardi would never have been able to get away with his scheme were it not for one thing.

"Corruption," said Osborn. "To me, that signifies corruption."

"Had the state Bar been doing its policing of attorneys, including Tom Girardi, to the level that they were supposed to, this scheme would've never gotten off the ground," Osborn said.

Officials with the California Bar did not immediately respond to the lawsuit.

In March, the bar did issue a public statement admitting its own breakdowns that enabled Girardi to do what he did to his clients.

"The magnitude and duration of the transgressions reveal persistent institutional failure and a shocking past culture of unethical and unacceptable behavior," the bar said on March 10 in conjunction with the release of reports detailing the actions of former staff and officials. "In recent years we have put in place many safeguards that serve both to prevent unethical or corrupt behavior and -- if it does occur -- to catch and address it quickly. That work continues."

The new lawsuit, filed by Osborn, is built in large part on the findings of those bar reports. It marks the opening of a fresh front in a scandal that has already shaken both the legal and entertainment worlds and has enveloped both Girardi and his estranged wife, who has insisted repeatedly that she was not aware of or part of Girardi's alleged crimes.

Girardi, 84, is facing federal criminal wire fraud charges in Los Angeles and Chicago, alleging that he diverted millions in clients' money to fund his lavish lifestyle. He has pleaded not guilty, and his attorneys are currently fighting to have a federal judge in California declare that Girardi is not competent to stand trial due to dementia. A hearing on the competency question is scheduled to resume Monday in Los Angeles.

Now in bankruptcy and being represented by taxpayer-funded lawyers, Girardi has lost his home and the trappings of success that infuriated the Agatons when they saw them on TV.

"The mansions," Ana Agaton said. "The mansions that he has, the life that his wife is living. Their lifestyle. Their lifestyle with money that don't belong to them."

The Agatons had moved to Colton, California, between Riverside and San Bernardino, dreaming of a better life for daughter Dahlia and her younger brother, "Arturito," as they called him. It was 17 years ago when their three-year-old son started coming down with the headaches and runny noses that would mark the beginning of the end. The family didn't know that the two cement plants that sandwiched their neighborhood were quietly polluting the community and preying on those who lived there, they said.

"My husband was supposed to take him to the park to start his first game that day," recalled Ana Agaton about her son. "And instead of that, we had to take him to the hospital. And he was over there at the hospital, he was screaming that he didn't want to be there, that he needed to go to play baseball."

Ana and Arturo were told their son had a malignant brain tumor, they said, and it was the result of hexavalent chromium coming from the cement factories. Radiation and chemotherapy followed, but Arturo Jr.'s little body could not escape the hand of death.

"We had to get on our knees one night, and ask the Lord to take him -- we asked the Lord that if he wasn't going to heal him, to take him because it was so hard to see him, to see him crying and screaming of the headaches," Ana Agaton said.

"'You gave him to us and you take him whenever you want. Take him please,'" she recalled telling God. "It was the most difficult time, but we had to do it."

Arturo Jr. died three years after his first symptoms appeared. By 2015, the Agatons were part of a class-action lawsuit brought by Girardi against Riverside Cement Holdings Co. The company settled for $31 million.

Now, the Agatons said, they find themselves on a long list of former Girardi clients turned victims.

Their new lawsuit against the California Bar seeks, among other things, unspecified financial damages and legal fees.