One day in June of last year, at a time when federal investigators were demanding security footage from former President Donald Trump’s Mar-a-Lago estate, Yuscil Taveras shared an explosive secret.

Taveras, who ran Mar-a-Lago’s technology department from a cramped workspace in the basement of the sprawling Florida property, confided in an office mate that another colleague had just asked him, at Trump’s request, to delete the footage that investigators were seeking.

Taveras later repeated that story to at least two more colleagues, who in turn shared it with others, according to people with knowledge of the matter. Before long, the story had ricocheted around the grounds of Trump’s gold-adorned private club and up the chain of command at Trump Tower in Manhattan, prompting Taveras’ superiors in New York to warn against deleting the tapes.

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But by then, Taveras had already balked at what prosecutors said was Trump’s request. Looking to steer clear of the investigation into whether the former president was hoarding classified documents at Mar-a-Lago, he told one colleague that he was unwilling to cross a line and potentially go to prison, according to another person with knowledge of the conversation.

Still, when he was summoned before a grand jury this spring, Taveras did not fully recount the incident. Only after prosecutors subsequently threatened to charge him for failing to tell all that he knew did Taveras shift course to become a potentially important witness in the case.

Facing indictment this summer, Taveras replaced his lawyer, who was being paid by Trump’s political action committee and also represented one of the former president’s co-defendants. Taveras then returned to the grand jury and offered a more detailed version of events, recounting how he had been asked to delete the surveillance footage. In exchange, prosecutors agreed not to charge him.

This account of Taveras’ turnabout, drawn from court records and interviews with nearly a dozen people who know him and are involved in the matter, reveals new details of the critical if at first reluctant role he played in helping investigators develop…