Ukraine’s national anti-doping body gave athletes advance notice of what were supposed to be random out-of-competition tests in a “brazen” scheme dating back nearly a decade, the World Anti-Doping Agency (WADA) said Tuesday.

WADA investigation – dubbed “Operation Hercules” – uncovered evidence that since 2012 the National Anti-Doping Organisation of Ukraine (NADC) had routinely tipped off athletes prior to testing.

Instead of conducting random, out-of-competition tests – a key pillar of the fight against drug cheats – the NADC would contact athletes to arrange for testing at the organisation’s offices the following day.

“‘Operation Hercules’ has convincing and corroborated evidence that NADC was engaged in the practice of telephoning athletes or contacting them through their coaches to request their attendance at the NADC, the following day, for testing,” WADA’s Intelligence and Investigations director Gunter Younger said.

“The evidence suggests that NADC would adopt this practice often before important international events and there were times when an entire discipline of the national team was present at the NADC awaiting testing.”

Investigators also found that the NADC categorised at least six in-competition athletes samples as out-of-competition samples ahead of the postponed Tokyo Olympics. The six samples in question were re-analysed by WADA but came back negative.

Younger said evidence indicated the samples were wrongly categorised in order to meet the minimum number of out-of-competition tests required to compete in the Tokyo Games.

Wrongly categorising a test sample as either in or out-of-competition could be significant because substances and methods are only prohibited in-competition, Younger said.

“In this way, a positive test could be incorrectly categorised as negative and an athlete could evade an anti-doping rule violation as a result,” Younger said.

The Operation Hercules findings will now be turned over to WADA’s Compliance Review Committee for possible sanction.

“‘Operation Hercules’ has raised serious questions about the integrity of NADC’s testing practices, and the competence of some staff,” Younger said.

“The apparent longevity and brazenness of these practices suggests significant organisational failings within NADC.”

WADA said investigators meanwhile had found evidence that an individual within the Ukrainian Athletics Federation was involved in trafficking of erythropoietin, the banned blood booster.

The individual in question has denied the allegation. Investigators have reported their findings to the Athletics Integrity Unit for its consideration.