Chinese officials in the US are searching for the exiled brother of a disgraced top aide to former President Hu Jintao, according to media reports.
Ling Jihua was charged with corruption and removed from the party last month.
The pursuit of his brother Ling Wancheng could overshadow a visit by President Xi Jinping to the US.
The US administration has warned China to stop sending undercover agents to the country to pressurise Chinese fugitives, the New York Times reports.
Mr Ling was demoted in 2012 after reports that his son had died in a high-speed Ferrari crash in Beijing.
He is accused of accepting huge bribes personally and through his family. His arrest is part of a crackdown on corruption by President Xi.
Ling Jihua's brother moved to the US in 2013 or 2014, according to media reports.
Beijing began an initiative called Sky Net in April to help bring to justice allegedly corrupt officials who had fled overseas.
The New York Times reports a programme called Fox Hunt involves clandestine operations to pressurise high-profile Chinese nationals into returning to China.
The US state department has now resorted to warning Chinese officials about the activities, the report says.
The newspaper said the undercover agents were working under the direction of China's ministry of public security and probably entering the country on tourism or trade visas.
Their tactics reportedly include threats to family members who remain in China.
In China, Ling Wancheng held a senior position in the state-run news agency Xinhua before pursuing business interests, according to media reports.
More than 930 suspects around the world have been repatriated to China since last year under the programme, the newspaper said.
China has been pushing for talks with the US on an extradition treaty.
The fugitives sought under Operation Fox Hunt are believed to be prominent expatriates, sought for economic corruption or what China considers political crimes.