The Associated Press reported House Foreign Affairs Chairman Tom Lantos ordered an investigation after documents were released that raised questions about what Yahoo knew when it shared information with authorities about a Chinese journalist.
Shi Tao, the journalist was sentenced to 10 years in prison for sending an email about Chinese media restrictions, the AP reported.
Lantos said that "covering up such a despicable practice when Congress seeks an explanation is a serious offense," the AP reported.
Jim Cullinan, a Yahoo spokesman, expressed disappointment to the AP that Lantos "is rushing to judgment on this issue, because the facts will support Yahoo's testimony to Congress."
"To do business with China's more than 100 million Internet users, U.S. tech companies must satisfy a government that fiercely polices Internet content. Filters block objectionable foreign Web sites; regulations ban what the Chinese consider subversive and pornographic content and require service providers to enforce censorship," the AP noted.