The Saudi government has said its dragnet followed an extensive investigation by a newly formed anti-corruption committee headed by the country’s crown prince, Mohammed bin Salman. The prince, who has fashioned himself as a reformer, is in the midst of a charm offensive to bolster diplomatic and financial ties to the West and is scheduled to visit Washington this month.

The detentions, however, have been almost entirely opaque. There have been no signs of collaboration with Western law enforcement and no charges made public, leading some critics to view it as a power and money grab rather than a bona fide anti-corruption effort. Saudi officials have denied that anyone has been mistreated, but people with knowledge of the detentions have said that as many as 17 of the detainees required medical attention because of abuse, and one later died in custody.

Given the insular nature of the country and the crackdown, Saudi officials are likely to make the most headway seizing assets within their own borders. Within Sheikh Amoudi’s empire, there is much to sort through.

He moved to the kingdom as a teenager. Although there are few firm details about how a commoner came to vast wealth, he managed to forge influential connections. The most important was Prince Sultan bin Abdel Aziz, who served as defense minister and crown prince before his death in 2011. Sheikh Amoudi ran businesses that depended on the prince’s money and position, associates said. Another of his allies was Khalid bin Mahfouz, a billionaire who later became enmeshed in the collapse of the Bank of Credit and Commerce International in 1991, at the time one of the largest private banks in the world.

In the 1980s, Sheikh Amoudi set up Mohammed International Development Research and Organization Companies, a conglomerate known as Midroc. Early on, his biggest deal was a multibillion-dollar project to build the kingdom’s underground oil storage capacity. Engineering and construction became core businesses for Midroc, but it operates everything from pharmaceutical to furniture factories in the region, according to its website. Sheikh Amoudi also owns half of a steel company called Yanbu, and a large chain of gas stations called Naft.