Tension in the Jackson family apparently developed when matriarch Katherine was briefly brought by family members to Arizona amid claims of fraud in Michael's will.
Michael's daughter Paris Jackson publicly expressed fears about her grandmother's condition while Katherine was away, but her uncle Jermaine Jackson claimed that the grandmother was simply under doctor's orders to rest.
This led to an alleged confrontation between Paris and her aunt Janet Jackson at the family's Calabasas home, but claims of any physical violence between the two were strongly refuted.
A law enforcement source has now told TMZ that the department has dropped an investigation into an alleged scuffle between other adults in the Jackson family on that day.
The probe was allegedly cancelled because the Jacksons chose not to cooperate with investigators, according to the source.
A spokesperson for the family declined to comment on the matter.
Katherine returned home to California days after her trip to Arizona began, and since that time the family have remained tight-lipped about the alleged feud.