Phoenix ? Former Senate Majority Leader George Mitchell warned baseball owners that a lack of cooperation with his investigation into steroid use would “significantly increase” the chances of government involvement.

Speaking to owners at baseball’s quarterly meetings, Mitchell said he intended to interview active players and raised the possibility that Congress or other government authorities could compel testimony.

“I believe it will be in your best interests, and the best interests of baseball, if I can report that I have received full cooperation from your organizations, and from others, in conducting this investigation,” Mitchell said in remarks that were released to reporters.

Mitchell cited last week’s Hall of Fame vote to underscore the importance of his investigation. Mark McGwire was picked on 23.5 percent of ballots – far below the necessary 75 percent needed for induction. The vote was viewed by many as the first referendum on how history will judge an age when bulked-up players came under suspicion of using performance-enhancing drugs. Baseball didn’t ban steroids until after the 2002 season.

“If nothing else, the results of the Hall of Fame voting last week, and the reaction to it, offer fresh evidence that this issue will not just fade away,” Mitchell said. “Whether you think it fair or not, whether you think it justified or not, Major League Baseball has a cloud over its head, and that cloud will not just go away.”

Mitchell cannot compel testimony. He warned the clubs that Congress or other federal or state authorities which do have subpoena power could get involved.