After flying under the radar for years, the case of Genaro García Luna is finally raising alarms in Congress, with one of the Senate's top Republicans demanding answers about how Mexico's highest-ranking cop was able to partner with DEA and FBI, "at the time that he funneled roughly 103,000 pounds of cocaine into the United States" for the Sinaloa Cartel. García Luna became the most senior Mexican law enforcement official ever convicted of narco-corruption when a Brooklyn federal jury delivered a unanimous guilty verdict on a five-count indictment that charged him with taking massive bribes to enable cartel drug smuggling, kidnappings, and murders while he was in office from 2001 to 2012. García Luna's position involved close collaboration with U.S. anti-narcotics agencies that operate in Mexico, and it gave him discretion over the spending of hundreds of millions in American tax dollars delivered as security aid. That money was supposed to go toward fighting the cartels, but his trial showed he was leaking sensitive intelligence, protecting drug shipments, and disrupting efforts to capture ... cartel leaders. On Feb. 22, a day after the guilty verdict, Iowa Sen. Chuck Grassley sent a letter to the heads of the DEA and FBI asking what the agencies knew about García Luna and when, and demanding evidence ... that could shed new light on the relationship. In short, Grassley wants to know if American tax dollars were being sent to Mexico while the DEA and FBI were tolerating García Luna's corruption.