Omeed Malik was a powerful figure in the hedge fund world. He was a managing director and helped run the prime brokerage business that raises money for hedge funds. Among his roles, Mr. Malik was an adviser to Jon S. Corzine, the former New Jersey governor and United States senator, as Mr. Corzine started a hedge fund, and he was a speaker at a high-profile hedge fund conference organized by Anthony Scaramucci, who briefly was White House communications director last year. Mr. Malik, a former lawyer at Weil Gotshal & Manges, a prominent New York firm, also was a member of the Council on Foreign Relations. He departed last week after an internal investigation into a young female banker’s accusation of inappropriate sexual conduct, according to people at the bank who were briefed on the investigation. Mr. Malik was known as a charismatic figure with close ties to the hedge fund world. His close ties to Mr. Corzine were forged while Mr. Malik worked at MF Global, the big commodities trading firm that collapsed in bankruptcy under Mr. Corzine’s leadership. Last year, Mr. Corzine sought to return to Wall Street with a hedge fund that Mr. Malik helped promote.