Theresa Neubauer was at work five years ago at a Georgia university when she got a phone call that stunned her.

Her son-in-law — a prominent fertility doctor who’d authored or edited several medical books — had just been arrested on suspicion of murder in the mysterious death of her daughter, Susann Sills, 45.

Susann’s body had been found at the bottom of a staircase in the couple’s suburban Southern California home in 2016.

Up until that April 2019 phone call, Neubauer said, her family…