The coaching team surrounding Kamila Valieva has come under fierce scrutiny after the 15-year-old Russian figure skater was engulfed by a doping controversy at the Beijing Olympics -- and none more so than Eteri Tutberidze.

After it was confirmed Friday that Valieva had failed a drugs test and could be kicked out of the Games, the hashtag "shame on Tutberidze" began trending on Twitter in Russia.

Russia's anti-doping agency RUSADA said that "an investigation has been initiated into the athlete's staff".

It did not name the 47-year-old Tutberidze and there is no suggestion of wrongdoing on her behalf, but it brings renewed focus on the notoriously strict methods of a coach who has trained up a team of brilliant young skaters tasked with winning gold in Beijing.

Valieva and her 17-year-old teammates Alexandra Trusova and Anna Shcherbakova, who are also Tutberidze's proteges, had been expected to dominate the women's singles -- one of the Games' most prestigious and scrutinised events.

Breaking her silence on the Valieva doping affair, Tutberidze told Russian television: "I am absolutely sure that Kamila is innocent and clean."

Tutberidze has been dubbed Russia's "Snow Queen" for her icy demeanour and no-nonsense coaching style.

She was thrust into the spotlight during Russia's home 2014 Sochi Games, where her then-15-year-old star Yulia Lipnitskaya mesmerised with a "Schindler's List" routine and took home gold in the team event too.

Tutberidze has since become one of the most sought-after coaches in the world. 

A striking figure with blonde curls and piercing brown eyes, she is a household name in Russia, where supremacy in the sport is a point of national pride.

But her rise to fame has been coupled with controversy over her methods after several students abruptly left her team.

"I prefer to tell my athletes the truth because they will hear flattery from others," Tutberidze told Channel One in an unusually candid interview in December, sitting with her puppy Michelle on her lap.

Dashed American dream 

Born into a family of five in Moscow, Tutberidze aspired to become a singles skater but a serious injury forced her to pursue ice dancing instead.

In the early 1990s she left the Soviet Union for the United States, but promises of an ice dancing job there fell through.

Stranded without work, she and her troupe struggled to make ends meet. 

They lived at a YMCA in Oklahoma City, where Tutberidze said she narrowly escaped the 1995 terrorist bombing that killed 168 people.

She eventually found work as a skating coach, but missed home.

Returning to a changed Moscow, she encountered "failure after failure" searching for work until she found a job with an ice circus, training amateurs.

She then returned to coaching and in 2008 joined the Khrustalny ice rink in Moscow, where she continues working today. 

The rest is skating history.

After Lipnitskaya's success at Sochi, another of her skaters, Evgenia Medvedeva, took both the European and World titles in 2016 and 2017.

The following year, two of Tutberidze's students dominated the Pyeongchang Olympics women's singles event.

Alina Zagitova took gold and Medvedeva, in a bitter loss, was left with silver. 

Also under Tutberidze's guidance, Trusova -- nicknamed "the Russian rocket" -- became the first female skater to land a quad Lutz and quad toeloop in competition -- technically challenging jumps that require four full rotations.

Just before they all headed to Beijing, Valieva, Trusova and Shcherbakova won all three medals at the Russian championships and the European championships.