Zhou Yuanqing and his businesswoman wife Zhou Lingying were taken away from their home in Wuxi in the eastern province of Jiangsu on December 1 by "discipline investigators from Beijing", the Beijing News said.
The husband is a brother of Zhou Yongkang, according to the report, who amassed huge power during his time as China's security chief and retired as a member of the Communist Party's all-powerful Politburo Standing Committee (PSC) in late 2012.
She was also involved in a liquefied natural gas station partnership with a company affiliated to state-owned China National Petroleum Corp., the oil giant once headed by the politician.
Rumours have been circulating for months that Zhou Yongkang is being investigated for corruption.
At least six high-ranking officials believed to have been his proteges have fallen since the once-in-a-decade power transition that anointed Xi Jinping as the ruling party's general secretary.
The New York Times in December cited "sources with elite political ties" as saying that Xi had given the go-ahead for the investigation of Zhou.
Yesterday, a spokesman for the Chinese People's Political Consultative Conference, a debating chamber that is part of the Communist Party-controlled governmental structure, avoided denying that Zhou was under investigation at a press conference.
