William Avery Rockefeller (November 13, 1810 – May 11, 1906) was the father of American oil tycoon, John Davison Rockefeller (July 8, 1839 – May 23, 1937) and William Rockefeller. He was a bigamist, a quack doctor, and a confidence trickster. An unreliable father, he played virtually no role in his son's business career, but he lived to a great age, and when the press heard rumours that the richest man in the world, then at the height of his notoriety as a monopolist, had a shameful family secret it went into a frenzy. Joseph Pulitzer offered a reward of eight thousand dollars for information about "Doc Rockefeller" who was known to be alive and living under a false name, but whose whereabouts were a family secret. Despite slender clues picked up from interviews with family members and an eighteen month search, the journalists failed to track him down before he died, and the full story wasn't exposed until two years later.

Reference

Titan: The Life of John. D. Rockefeller, Sr, by Ron Chernow.