Panasonic Avionics, a subsidiary of Panasonic Corporation (NYSE:PC), is under investigation by U.S. officials who are looking into whether the electronics giant paid bribes to overseas airline employees in an effort to land more contracts.

According to company documents, as cited by the Wall Street Journal, the Panasonic unit has received a subpoena requesting communications between Panasonic Avionics, consultants and others.

The subpoena also seeks documents related to payments to the airline employees and government officials, the newspaper said. Notices have reportedly been sent to executives and employees in Asia, Europe and the Middle East.

While the Journal hasn't specified which agency is investigating the unit, the U.S. Foreign Corrupt Practices Act, which bars U.S. companies and companies listed on U.S. stock exchanges from paying bribes to foreign government officials, is enforced by the Department of Justice and the Securities and Exchange Commission.

Panasonic Avionics, based in Lake Forest, Calif., is a supplier of in-flight music and video entertainment, in-flight shopping, phone service, email, video games and GPS flight location display. The unit is an approved supplier to both Boeing Co. (NYSE:BA) and Airbus and the primary entertainment provider for a large number of airlines worldwide.

In 2009, Panasonic Avionics and Lufthansa announced a partnership in which the electronics provider would supply the airline with a satellite-based broadband technology offering passengers in-flight Internet and cellphone connections. It's unclear whether that deal is under investigation.

In its 2012 annual report, the company said it retained the top global market share in the in-flight entertainment systems segment, posting "double-digit growth in sales."