McDonald, 56, was found dead in his car near a strip mall in Dartmouth, Massachusetts on Sunday afternoon. Police are still investigating.
"The preliminary investigation concludes that this was an apparent suicide," Gregg Miliote, a spokesman for Bristol County District Attorney Sam Sutter said.
McDonald won praise for growing Rockefeller & Co, the New York-based family office established by oil tycoon John D. Rockefeller in 1882 to manage the dynasty's assets, into a broader investment
