In his statement issued Tuesday, Bo Guagua said, "I have never lent my name to nor participated in any for-profit business or venture, in China or abroad."

He said in the statement on the website of the Harvard Crimson newspaper that he had been involved in a not-for-profit social-networking website in China, the aim of which was to "assist NGOs in raising awareness of their social missions and connecting with volunteers." He said the project was based out of the Harvard Innovation Lab, with the participation of fellow students and friends, and was still under development. Friends say the website is called guagua.com.

He said he had no comment about the parallel investigations into his father and mother.

Bo Guagua's whereabouts were unclear. As The Wall Street Journal reported last week, a person familiar with the matter said he appeared to have left his apartment in Cambridge, Mass., the week before, escorted by private security guards.

He said his tuition and living expenses at Harrow, a British private school, as well as Oxford and Harvard universities had been funded by scholarships "earned independently" and by his mother's earnings as a successful lawyer and writer.

He didn't, however, say who provided the scholarships.

Bo Guagua also said that he had never driven a Ferrari or visited the U.S. ambassador's residence in Beijing, and hadn't been to the U.S. Embassy there since 1998. The Wall Street Journal reported in November that people familiar with the episode early last year said he had arrived at the U.S. Ambassador's residence in a red Ferrari to pick up a daughter of Jon Huntsman, then the ambassador, for a dinner appointment.

—Jeffrey Ng and Alex Frangos contributed to this article.