Add Yahoo as a preferred source to see more of our stories on Google. It was the week of Kimbal Musk’s 40th birthday in September 2012, and invitations went out for his party that Saturday at 7 p.m.

Mr. Musk has tried to put distance between himself and the disgraced financier Jeffrey Epstein, but emails show the two were on friendly terms. By Michael C. Bender Sharon LaFraniere and Ryan Mac ...