Maurice Greene's Coach in New Balco Link

John Smith, the man regarded as the world's leading coach, whose list of athletes includes the Olympic 100 metres champion Maurice Greene, is the latest high-profile name to be dragged into the biggest steroid scandal in history.

It has been reported that in October 2001 the American had a three-hour meeting with Victor Conte, the founder and owner of the Bay Area Laboratory Co-Operative, and at its conclusion signed a document titled "Agreement Not to Disclose or Use Confidential and Proprietary Information".

It has also been alleged that one of Smith's sprinters, Ato Boldon, Trinidad's Olympic 100m silver medallist in 2000, signed a similar document six weeks later.

The documents, as well as three email messages from Conte to Smith in October and November 2001, provide an uneasy link between one of the world's top sprint camps and a scandal which grows bigger each day. Conte and three other men have been charged with running a ring to distribute illegal steroids.

Emanuel Hudson, Smith's lawyer and president of HSI, the athletics management company they set up together, denies the story. "If you are going to do something illegal, why would you sign a disclosure document?" he said. "Do you think a crack dealer on the corner would say he would want you to sign a disclosure agreement before he sells you the crack?"

Hudson said that emails Smith received from Conte's company were sent without his knowledge. "John Smith got spammed," he said. "John Smith met with Victor Conte just like several people in track and field met with Mr Conte."

Among the athletes coached by Smith is Torri Edwards, promoted to the gold medal position in the 100m in last year's world championships after Kelli White was stripped of the title and banned for two years on her admission to the United States Anti-Doping Agency last week that she had been using banned drugs obtained from Balco.

The revelations came to light five days after Greene had called for draconian punishments for anyone associated with Balco. The publicity surrounding Smith did not appear to affect Greene in Carson, California, on Saturday in clocking a wind-assisted 9.86sec to win the 100m.

Marion Jones won the 100m in 10.99 at the same meeting and won the long jump with 7.13m, but her partner Tim Montgomery, the world 100m record holder, finished only sixth in Mexico City in 10.24.