The freshman players have been accused of stealing sunglasses from a Louis Vuitton store next to the team's hotel in Hangzhou.
Per Chinese law, the three players could face significant prison sentences of three to 10 years if convicted of grand larceny.
A senior White House official said the players had been given relatively light treatment due to Trump's intervention.
Trump had raised the issue with Xi at a dinner held during the US leader's November 8-10 state visit to Beijing. They were not on the team's return flight to the United States on Saturday.
Asked about the trio and Trump's discussing the issue with Xi, China Foreign Ministry spokesman Geng Shuang told a daily news briefing in Beijing that he was unable to provide any further information.
Since the matter did not occur on the court, it would be up to UCLA whether the players will be punished, Scott said. On Monday, ministry spokesman Geng Shuang said that three American men were being investigated in the eastern city of Hangzhou for alleged theft and that China and the US were in contact over the matter.
UCLA, one of the most storied names in U.S. college basketball with 11 men's NCAA championships, won Saturday's game in Shanghai 63-60 without the three players. UCLA is scheduled to host Central Arkansas Wednesday at Pauley Pavilion.
According to Arash Markazi of ESPN, the three players will have to stay in China for another week or two while this matter gets resolved by Chinese authorities. During the questioning, Ball, Hill and Riley were accompanied by interpreters and UCLA team representatives, according to ESPN.