World 100-metres champion Justin Gatlin, twice suspended for doping, could face another scandal after The Daily Telegraph reported that members of his entourage offered to sell undercover reporters performance- enhancing drugs.

The 35-year-old American sprint star has sacked coach Dennis Mitchell, according to the report, which revealed Mitchell and athletics agent Robert Wagner offered to provide false prescriptions for banned performance-enhancing substances and smuggle those drugs into the United States.

The Telegraph said investigations into the actions of those connected to Gatlin are being investigated by the Athletics Integrity Unit (AIU), set up this year by the International Association of Athletics Federations (IAAF) and the US Anti-Doping Agency (USADA).

“Investigations stemming from tips and whistleblowers play a critical role in anti-doping efforts,” an unnamed USADA spokesman told the newspaper.

“We are presently coordinating with the Athletics Integrity Unit in order to investigate these claims fully.”

IAAF president Sebastian Coe, who said Gatlin’s win over Jamaican legend Usain Bolt last August at London in the world 100m final was not good for the sport, told the newspaper the claims were very serious.

“These allegations are extremely serious and I know the independent Athletics Integrity Unit will investigate in accordance with its mandate,” Coe said.

That came even as the 2017 world champion had legal advisers release five years of official drugs tests that showed he was clean. Gatlin was banned for doping in 2001 for one year and in 2006 for four years.

Gatlin’s longtime agent, Renaldo Nehemiah, told the newspaper that Wagner had represented Gatlin only two to three times and that Gatlin was not present when banned substances were discussed with Mitchell or Wagner.

Mitchell and Wagner allegedly offered to supply and administer testosterone and human growth hormone for an actor training for a film on athletics at a price of 250,000 (187,000 pounds), according to the report.

The newspaper said it began its investigation in July after hearing of agents and trainers involved in supplying drugs to athletes, reporters posing as film production company representatives seeking people to train a film star.