He struck billions of dollars’ worth of deals in Russia, Eastern Europe and Africa. He sought business with war-torn places like Chad and with international pariahs like North Korea.

Ye Jianming, a fast-rising Chinese oil tycoon, ventured to places only the most politically connected Chinese companies dared to go. But what he wanted was access to the corridors of power in Washington — and he set out to get it.

Soon, he was meeting with the family of Joseph R. Biden Jr., who was then the vice president. He dined with R. James Woolsey Jr., a former Central Intelligence Agency director and later a senior adviser to President Trump. He bestowed lavish funding on universities and think tanks with direct access to top Washington leaders, looking for the benefits access can bring. He asked one former American security official: If he bought oil fields in Syria, could the former official persuade the American military not to bomb them ?

That effort has unraveled. Mr. Ye is in Chinese custody and is under investigation for unspecified crimes. The trial and conviction in New York last week of one of his top lieutenants, Patrick Ho, showed that company officials used bribery to win oil and energy contracts in Africa.