Two police detectives, one from Northglenn, another from Thornton, are suing their respective chiefs and other drug task force supervisors who they say retaliated against them.Northglenn Detective Daniel Joyce and Thornton Detective Robert Lopez filed a lawsuit in federal court last week claiming they were punished for blowing the whistle that a crooked cop tipped a drug-trafficking kingpin that federal and local agents were about to conduct what became the biggest marijuana seizure in Colorado history. Read the detectives' federal lawsuit The case centers on the investigation of Thornton restaurateur Dan Tang. He pleaded guilty in November to money laundering for the sophisticated marijuana growing operation inside dozens of upscale suburban homes around metro Denver. Before his arrest, Tang was known as the politically connected owner of the Heaven Dragon restaurant, who personally served President George W. Bush his favorite dish -- Peking duck -- whenever he visited Colorado. His restaurant walls boasted photos of himself with the former president, along with photos of former Vice President Dick Cheney and former Colorado Gov. Bill Owens. They were among a parade of politicians who dined at the popular eatery.Then came Operation Fortune Cookie, the joint investigation by the North Metro Task Force and the U.S. Drug Enforcement Investigation that began in late 2007. The probe culminated in a two-day series of raids in February 2008 when investigators seized 24,056 marijuana plants and recovered more than $3 million in cash, according to court records. The task force had to rush the raids after overhearing Tang say in a wiretapped phone conversation that he had received an anonymous letter tipping him off to the massive investigation about to expose his drug-trafficking ring, according to court records. The never-identified tipster had detailed knowledge of Tang's drug operation and the investigation. It warned the businessman that his phone was being tapped and that federal authorities where cooperating with the Chinese government to track drug profits being funneled to that country, revealed the one-page letter first published by Westword magazine. "Translators have been provided [to investigators]. So do not think you are safe speaking in your native tongue or dialect," the tipster wrote Tang, a Chinese immigrant. "You cannot trust anyone either, because there is/are (a) person/people providing information about the inner workings of this organization, marijuana grows, set-ups, harvesting, sales, distribution ..." the tipster wrote. The writer provided Tang with a temporary phone number he could call if he wanted to "avoid prosecution" and losing all his money, restaurants, houses, cars -- and his freedom. Joyce and Lopez, who at the time were detectives on the North Metro Task Force, state in the lawsuit that the main suspect of the leak was one of their supervisors. The task force is comprised of investigators from several law enforcement agencies in Adams and Broomfield Adams counties and investigates drug trafficking in that region. It is governed by a board of police chiefs and sheriffs in those counties. The detectives say their superiors "allowed the main suspect in the federal investigation into the leak in the Tang case to stay in a supervisory position at the Task Force, thus allowing him to remain in a position to control the further investigation of the case, and the lives of the officers involved in the investigation, including detectives Lopez and Joyce," the lawsuit states. An investigation began, and both officers cooperated with investigators from the DEA, the IRS and other agencies. Joyce, who was the lead investigator on the pot trafficking case, "also spoke out (to federal investigators) about the failure of the Task Force and/or its refusal to adequately investigate and prosecute government officials and business persons associated with illegal drug activities," the lawsuit said. In punishment for speaking out, the lawsuit alleges, that Joyce and Lopez were retaliated against by Northglenn Police Chief Russell Van Houten, Thornton Police Chief James Nursey, Westminster Sgt. Jack Bell, Thornton Sgt. Dante Carbone and Broomfield Commander Tim Hersee, all of whom oversaw Joyce's and Lopez's work on the task force. The detectives said superiors demeaned them as self-righteous "rogue" cops and reprimanded them for cooperating with DEA leak investigators, the lawsuit stated. They were eventually pulled off the drug case and "forced" from the task force. Joyce said another task force supervisor, Adams County sheriff Sgt. Richard Reigenborn, began watching him wherever he went, even after he returned to work at the Northglenn police headquarters, the lawsuit said. Joyce also stated that his home was "under surveillance by unknown persons." Both Chief Nursey and Chief Van Houten told TheDenverChannel.com Thursday they could not comment on the lawsuit because they have not been served with it. But Nursey agreed to speak about the background of the drug investigation and the tip-off letter probe. The Thornton police chief said he and other task force board members invited the DEA into the local drug-trafficking investigation in late 2007. The board also welcomed the DEA to join the probe into who sent Tang the tip-off letter, he added. The task force commander sent a memo to all its members encouraging them to cooperate in the leak probe and provided the names and phone numbers of the individual investigators, which included DEA agents and two Adams County law enforcement officers who had no role in the task force, Nursey said. When an exhaustive investigation could not identify the leaker, Nursey said he and another police chief asked the head of the Denver FBI to investigate allegations of corruption and cover-up that have swirled around the task force probe since early 2008. The FBI probe remains open. "That leak was investigated upside-down, inside-out and backwards. I'm telling you, no stone was left unturned," Nursey told TheDenverChannel.com. "And they could not determine who the leaked the information to Dan Tang." "I believe the board of governors of the task force has been diligent in pursuing this (leak case) step-by-step," Nursey said. "There's been an assumption by the media that that (leak) came from the task force," the chief added. "But there are numerous places where that leak could have come from." The detectives' lawsuit, however, alleges Joyce and Lopez told by task force supervisors to not talk with DEA investigators and to stop spreading rumors and negatively affecting morale."Lopez and Joyce said they repeatedly complained about mistreatment to their respective police chiefs and Hersee, the task force commander. They said their bosses "refused to take any action to remedy the situation," the lawsuit stated.Instead, the lawsuit said, that Lopez's boss, Chief Nursey, "publicly called Detective Lopez and others who cooperated with the DEA in the investigation of the task force leak 'rogue' and 'self-righteous' police who were 'friends with criminals.'" The two detectives said they were subjected to "possible physical danger ... by the refusal of defendants to remove those suspected of corruption, including leaking information to drug suspects," the lawsuit said.The below video of a 2008 Operation Fortune Cookie raid was first published by Westword magazine.