This was claimed by Russian Curling Federation President Dmitry Svishchev, who reiterated his view that somebody deliberately tampered with the sample.

"Finding the guilty one is the only thing that would help to partially or completely acquit Alexander," Svishchev told TASS, Russia's official state news agency. 

"It will require some time, which we do not have because an athlete's career is very rapid.

"We have received a letter from prosecutors concerning the preliminary investigation results.

"One thing is clear [from this letter] that Aleksandr is innocent, he never consumed meldonium and there was no registered fact of negligence."

Krushelnitckii, initially the winner of a mixed doubles curling bronze alongside his wife, Anastasia Bryzgalova, at Pyeongchang 2018, lost the medal after failing two drugs tests for meldonium during the Games.

A plan to appeal to the Court of Arbitration for Sport anti-doping division was withdrawn and the failure in February was accepted.

This was a tactical strategy to ensure Russia's suspension from the International Olympic Committee was lifted as soon as possible, however, and Russian figures have long protested his innocence.

Svishchev has repeatedly claimed tampering and suggested how there are similarities between the Krushelnitckii doping case and the country being blamed for the attempted murder of former spy Sergei Skripal and his daughter in Salisbury.

He has alleged that the substance may have been ingested into his food.

It is not clear who the supposed tamperer is, however, and there appears no chance of him formally being cleared by international bodies.

Athletes are responsible for whatever is found in their body under the World Anti-Doping Code.

Krushelnitckii has also denied speculation that the failure was due to an ex-girlfriend spiking him.