Chuck Blazer, the soccer official who turned into a federal informant and became a central figure in the 2015 FIFA corruption scandal, might not be done revealing secrets. Blazer, a member of FIFA’s governing council for nearly two decades, secretly cooperated with United States authorities for years before the Department of Justice shocked the soccer world with its sweeping indictment of dozens of soccer leaders and marketing executives in May 2015. Blazer died in 2017, before he could be sentenced for his crimes. He died owing millions to creditors, including the Internal Revenue Service and his former employer, the Confederation of North, Central America and Caribbean Association Football, one of soccer’s six regional governing bodies. And now the I.R.S. and the soccer association, known as Concacaf, are among the groups with access to eight storage lockers in New Jersey that hold a trove of Blazer’s personal effects. Blazer eventually pleaded guilty — secretly — to 10 charges, including bribery, money laundering and tax evasion, in 2013. Blazer’s girlfriend in the last years of his life, Mary Lynn Blanks, said in an interview that she was aware of the lists Blazer had made, and confirmed that as many as 100 names were on them, including several officials from the Americas who were eventually indicted. Blazer was for decades the most senior American in world soccer, wielding power through his Concacaf post but also his seat on FIFA’s governing body from 1996 to 2013. Earlier this year, for example, Concacaf settled a lawsuit with Blazer’s estate in which it accused Blazer of using a series of companies to cheat the Miami-based organization out of millions of dollars over two decades. Concacaf is unlikely to see any of the $20 million settlement, however, given that the I.R.S. holds priority in its efforts to recover almost as much in unpaid federal income taxes. In a 2013 guilty plea, Blazer acknowledged that for years he had been accepting bribes linked to the awarding of soccer tournaments, including several World Cups, and for lucrative television and sponsorship contracts. Elizabeth Manzo, the administrator for Blazer’s estate, told the court last month that Blazer’s assets were worth less than $1 million. He forfeited $1.9 million when he pleaded guilty. The Trump Tower apartments were rented and paid for by Concacaf.