Cities including London and NY have for months been vying to be awarded the deal, but Saudi Arabia's energy minister, Khalid al-Falih, last week said that the company was too important to risk a transaction in the U.S., because of litigation concerns that could stem from existing lawsuits against other oil firms for their role in climate change.
The newspaper interviewed relatives, advisers, associates of the detainees, as well as Saudi officials, who denied the allegations.
Saudi King Salman's order to establish new anti-corruption units as part of the kingdom's anti-graft campaign comes as fresh revelations have emerged of how detainees swept up in the campaign were treated and where their assets have gone.
A doctor and two other people briefed on the condition of the body said that it had burn marks that appeared to be from electric shocks.
Saudi officials did not immediately respond to AFP's request for comment, but the New York Times quoted the government rejecting the abuse claims as "completely untrue".
The report also said that more than a dozen of the prisoners were abused while they were being held, and that numerous assets of the 381 princes, ministers and tycoons have yet to be seized.
Gen. Qahtani, an officer in the Saudi National Guard who was believed to be about 60, was not wealthy himself, so his value as a major anti-corruption target is questionable.
Crown Prince Mohammed has fashioned himself into something of a renaissance man in the conservative Sunni Muslim kingdom, ushering in a series of social reforms in recent months.
Members of the Qahtani and Abdullah families have been afraid to discuss the general's death publicly for fear of further retribution, several people who have spoken to them said.