The investigation follows British corporate investigator Peter Humphrey's complaint against CCTV and its international division, China Global Television, for airing what he says was his forced confession while imprisoned in China. He says that violated U.K. broadcasting rules.
Humphrey and his wife were hired by pharmaceuticals maker GlaxoSmithKline to look into a security breach, but were themselves arrested after the Chinese government began investigating alleged bribery at the company.
Ofcom promised "appropriate action" if it found rules were broken. CGTN, which is available on free and pay TV in the U.K., didn't respond to emailed requests for comment.