The American writer Paul Auster, who became famous in the late 1980s with the detective novels “The New York Trilogy”, lost his granddaughter as well as his son.
Daniel Auster was found dead in New York on Tuesday.
The forty-four-year-old, who took drugs as a teenager, is said to have died of an accidental overdose.
Auster was arrested two weeks ago and released on $250,000 bail for the time being.
Prosecutors accused him of being responsible for the death of his daughter Ruby.
The ten-month-old girl was found dead in her father's apartment in Brooklyn in early November.
The autopsy revealed the child died of a fentanyl and heroin overdose while Auster was supervising him.
The 44-year-old admitted to injecting himself with heroin after his wife Zuzan Smith left for work.
Under what circumstances the drug got into Ruby's body remained open.
Prosecutors charged him with manslaughter after Auster's arrest.
The New Yorker was from Paul Auster's first marriage to author and translator Lydia Davis, who ended in divorce in 1978.
Four years later, Auster, one of the United States' best-known writers, married author Siri Hustvedt.