The mother of a 6-year-old boy who died after falling down stairs at a San Diego County mansion is seeking to reopen the investigation into his death.

U-T San Diego reports that Dina Shacknai and her representatives met with Coronado police and county medical examiner's staff last week. They presented results from two hired experts that concluded the July 2011 death of Max Shacknai was likely the result of an assault.

Authorities have concluded that Max -- the son of pharmaceutical tycoon Jonah Shacknai -- accidentally plunged over a stairwell banister while in the care of his father's girlfriend, Rebecca Zahau.

Two days after the fall, Zahau's nude, bound body was found hanging in the mansion.

That death was ruled a suicide but Zahau's family is challenging that ruling.