Toronto police have been called in to help the Federal Bureau of Investigation and U.S. prosecutors in the perjury and steroid investigation case against Major League Baseball great Roger Clemens.

CBC News has learned a Toronto police fraud investigator recently showed up at the headquarters of the Toronto Blue Jays with a court order demanding sensitive team medical records. The detective with the city's downtown 52 Division fraud unit carted away a bankers box filled with evidence.

Clemens is at the centre of a multi-year scandal over doping in Major League Baseball, accused by a number of former teammates and a trainer who claim one of baseball's all-time greatest pitchers used steroids and human growth hormones.

Clemens has repeatedly denied the accusations, including under oath in February 2008 before the U.S. Congress House Committee on Oversight and Government Reform.

"Let me be clear. The answer is no," Clemens testified. "I did not use steroids [or] human growth hormone and I have never done so."

But last month the FBI and U.S. prosecutors charged Clemens with obstruction of Congress, making false statements and two counts of perjury, which carry a maximum penalty of 21 months in prison and fines totalling $1.5 million US.

Clemens has pleaded not guilty.

Prosecutors looking for hard medical evidence

Toronto police demanded medical records and concrete documentary evidence during their recent visits to the Blue Jays head office as U.S. prosecutors try to sort out a major-league "he said, he said" involving Clemens and his former trainer.

Police presented the Jays with a court order asking for specific items, including blood test results, MRI records, photos and evidence related to Clemens' health issues during his time with the team.

Clemens, whose performance lagged for several years, joined the Blue Jays as a free agent in December 1996, and played for two seasons in 1997 and 1998. During this period his winning statistics skyrocketed, fetching him two back-to-back Cy Young awards.

The bulk of the accusations against Clemens are based on the word of Brian McNamee, who was hired by the Toronto Blue Jays in 1998 as a strength trainer and conditioning coach to work closely with Clemens.

(McNamee moved on with Clemens when he was traded to the New York Yankees and was his personal trainer until 2006. )

McNamee has since co-operated with police in a number of investigations into sports doping, and testified in 2008 that his former employer repeatedly asked him for help to inject banned substances.

"During the time I worked for Roger Clemens, I injected him on numerous occasions with steroids and human growth hormone," McNamee told the 2008 congressional hearings in a prepared statement. "I am not proud of what I have done and I am not proud to testify against a man I once admired … To those who have suggested I take some personal satisfaction taking down Roger Clemens let me assure you nothing could be further from the truth."

The 2007 Mitchell Report by U.S. Senator George Mitchell also documented claims by McNamee and other players that Clemens injected performance-enhancing drugs.

Clemens has steadfastly denied the claims and has stated that during his time with the Blue Jays he injected Vitamin B12 as he fought off an infection involving a skin abscess.

Jay Stenhouse, vice-president of communications for the Toronto Blue Jays, told CBC News in an email the team doesn't comment on matters that are before the court other than to add it's complying "with all valid legal process."