Abyssinian Baptist Church is one of the oldest Black churches in America, and certainly one of the most storied. As a college student at Columbia University, Barack Obama often lingered in the back pews during Sunday services, taking in the sermon and the choir. Hundreds of mourners have gathered at the 216-year-old institution in recent years for the memorial services of Cicely Tyson and André Leon Talley.

It’s the kind of church where networking mixes with Bible study, and the roll reads like a who’s who list of Black intelligentsia and entrepreneurship.

In 2017, when Mara Porter, a member of the church, found a Harlem brownstone to buy, she was struck by the charming real estate agent who had listed it. He was also a deacon at the church. A year later, Ms. Porter and her husband, Tommie Porter, hired the deacon as a contractor to lead the renovations of the $1.44 million house. “We really loved the idea of keeping it in the community,” said Ms. Porter, 44, host of “CrimeFeed” on Investigation Discovery.

The business deal between the parishioners, however, collapsed spectacularly, ensnaring the church and its membership in a six-year saga of multiple lawsuits, closed-door meetings at the church, a public spat in a Harlem restaurant, a bankruptcy filing by the deacon and a criminal investigation.

The Porters and other members of the church accused the deacon, Jerome Yeiser, of absconding with money in lawsuits filed against Mr. Yeiser by the Porters and another church family. The Porters wanted Mr. Yeiser prosecuted for grand larceny, for failing to pay subcontractors and misspending funds. In 2019, the Manhattan district attorney’s office, then led by Cyrus R. Vance Jr., opened a criminal investigation into Mr. Yeiser.