“I even had that list — there were two groups of people on the list, the people who he was involved in business that had a chart, one page would say person’s name, their relationship to him and their phone number, and whether or not he would allow them to be wiretapped,” Blanks said.

Blazer, a large man with an appetite for the finer things in life, 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. That position on FIFA’s executive board granted him a vote on the awarding of valuable hosting rights and a say in other contracts during an era when many of those transactions, investigations later showed, were rife with bribery and self-dealing.

In addition to the audiotapes and documents, the lockers contain other reminders of Blazer’s life in soccer, including oversize FIFA suits that were tailored for Blazer’s immense frame, as well as other items whose value is unlikely to satisfy the millions of dollars he owed his creditors when he died.

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.

Elizabeth Manzo, the administrator for Blazer’s estate, told the court last month that Blazer’s assets were worth less than $1 million.

In his lifetime, Blazer had frequently explained his lavish lifestyle to anyone who asked as the fruit of his success as a day trader of considerable skill. Visitors to his apartment in Trump Tower in Manhattan often would find him seated at a desk behind a computer screen, from where he said he executed his investment strategies.

The truth, later revealed in court documents, painted a far different picture of his income streams. 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.