When police officers broke down the door at the Peninsula Hotel in 2010, the evidence of what had happened inside Room 1603 seemed fairly clear.

Gigi Jordan, a multimillionaire pharmaceutical executive, was on the floor, disoriented and babbling. Her 8-year-old son lay on a nearby bed — stiff, cold, still. There were scores of pills and bottles of alcohol scattered about.

“I want a lawyer,” she muttered to the first officers who asked her what she had taken, according to prosecutors. To another officer, she said she wanted to die.

Four and a half years later, Ms. Jordan, 53, will be tried on murder charges in State Supreme Court in Manhattan. Opening statements in the trial, which is expected to last two months, are to begin Wednesday.