A year and a half after the death of Aretha Franklin, her tumultuous estate has again been thrust into confusion with the pending resignation of the singer’s niece as executor — a position she had accepted shortly after Franklin’s death with the full support of the singer’s four sons.

The niece, Sabrina Owens, wrote a letter to her lawyer on Thursday announcing her “intent to resign,” which was submitted in probate court the same day. In her letter, she described the disputes between family members that have led to recriminations in court papers. The judge overseeing the case is expected to consider Ms. Owens’s petition at a hearing on Tuesday.

The departure of Ms. Owens, who works as an administrator at the University of Michigan, comes as a number of major projects for the estate near completion. A biopic starring Jennifer Hudson — whose casting had Franklin’s personal blessing — has been shooting in Atlanta, and a season of the National Geographic channel’s show “Genius,” devoted to Franklin, is scheduled to air in May.

When Franklin died at 76 in August 2018, her family believed she had no will. Under Michigan law, that meant her assets would be divided equally among her four grown sons, who unanimously backed Ms. Owens, their cousin, as the estate’s “personal representative,” or executor.