A House panel on Thursday subpoenaed confidential company documents that a former Toyota lawyer has said proves the automaker routinely concealed evidence from the courts and federal regulators, a committee staffer said.

The subpoena was issued as part of an investigation by the House of Representatives Oversight Committee into Toyota Motor Corp's response to complaints of uncontrolled engine acceleration that led to a global recall of 8.5 million vehicles, Kurt Bardella, a committee staff spokesman, told Reuters.

Dimitrios Biller, who headed a corporate legal team that defended Toyota in rollover-accident lawsuits, took some 6,000 internal documents with him when he left Toyota in 2007, and has since sued the automaker under U.S. racketeering laws. He has said the documents support his allegations that the company systematically hid or destroyed legal evidence that would have led to costly trials in the United States.