Updated

The law firm that produced the Mitchell Report investigating performance-enhancing drugs in baseball is fighting former pitching star Roger Clemens over access to evidence it collected against him.

DLA Piper filed a motion in federal court in Washington on Friday to quash Clemens' subpoena for material it collected accusing the pitching great of using steroids and human growth hormone. In 2006, Major League Baseball Commissioner Bud Selig hired former Sen. George Mitchell, then a partner at the firm, to investigate allegations that players used drugs.

Clemens wants the firm to turn over material related to its interviews with his longtime personal trainer Brian McNamee, who told investigators he injected Clemens with performance-enhancing drugs; admitted steroid user and retired player Jose Canseco; and former New York Mets clubhouse attendant Kirk Radomski, who McNamee said provided the drugs Clemens used.

The firm said it has 20 internal documents requested by the subpoena that are covered by attorney-client privilege, including notes taken during interviews and memos describing their interviews with Radomski, McNamee and Canseco and with Canseco's attorney about Canseco's online drug purchases. The firm reported that it has turned over a declaration from one of its attorneys and four "items of correspondence" to Clemens.

Clemens wants the evidence to defend himself in a criminal trial over whether he lied to a congressional committee that held hearings on the Dec. 13, 2007, Mitchell Report, likely looking for weaknesses or inconsistencies in witness testimony. Clemens maintained throughout his testimony that he never used performance-enhancing drugs during his 23-season career, but prosecutors charged him with perjury, false statement and obstruction of Congress.

Clemens' legal team served subpoenas on the law firm and the House Oversight and Government Reform Committee that held the hearings in 2008, asking for all summaries, notes and memoranda related to their investigations. U.S. District Judge Reggie Walton said the firm and the committee had to respond by Friday. A committee spokesman said the House's counsel's office would respond by the midnight deadline.

Clemens attorney Rusty Hardin told Walton he expected that the committee may try to quash the subpoena by arguing that it would violate the separation of powers between the legislative and judicial branches of government.

Clemens subpoena to the committee covers its communications with the three men cited in the subpoena to the law firm and with 17 other people, including retired baseball players Chuck Knoblauch, C.J. Nitkowski and Andy Pettitte and staff from all four teams Clemens played for — the Boston Red Sox, Toronto Blue Jays, New York Yankees and Houston Astros.

Walton has scheduled an April 21 hearing for arguments over the subpoenas. Walton predicted that the dispute could end up in appeals court, but he hoped it wouldn't further delay the trial, currently scheduled for July.