Russia faces fresh accusations of tampering with doping data, which could affect its chances of competing in next year's Olympics. That's just the latest development in a five-year saga of revelations about widespread drug use by Russian athletes that has marred at least the last five Olympic Games.

Here is a timeline of the drug use, investigations and cover-ups:

Feb. 2014 — Russian President Vladimir Putin opens the Winter Olympics in Sochi, the first time Russia has hosted the Olympics since the collapse of the Soviet Union. The Russian team surprises many onlookers by finishing on top of the medal table, with nearly twice as many medals as it won in 2010.

Dec. 2014 — German television channel ARD reports on allegations of corruption and systematic doping throughout Russia. Reports include accusations from former Russian Anti-Doping Agency official Vitaly Stepanov and his wife, Yulia, an 800-meter runner who had been banned for doping. The Stepanovs go into hiding, saying they fear for their safety.

Nov. 2015 — Citing a report by its former president Dick Pound, WADA declares Russia's anti-doping agency noncompliant and shuts down the national drug-testing laboratory. Track's governing body, the IAAF, suspends the Russian track federation in a ban that remains in place today.

May 2016 — The New York Times publishes explosive testimony by Grigory Rodchenkov, the former director of the anti-doping laboratory in Moscow. He says he switched out dirty samples for clean ones as part of a state doping program at the 2014 Winter Olympics and other major events. A follow-up investigation helmed by Canadian lawyer Richard McLaren flags hundreds of covered-up doping cases in dozens of sports. The International Olympic Committee starts retesting old samples from the 2008 and 2012 Olympics, eventually banning dozens of athletes from Russia and other countries.

Aug. 2016 — Russia competes at the Olympics in Rio de Janeiro with a reduced squad after dozens of athletes fail vetting of their drug-test history by sports federations. The IOC resists calls to ban Russia entirely, but the Paralympics kick Russia out. Russia's Olympic weightlifting team is barred entirely for bringing its sport into disrepute and the track team consists of just one athlete, Darya Klishina, who gets a waiver to compete because she's based abroad. The Russian team is fourth in the Olympic medal count.

Aug. 2017 — Nearly two years into its track ban, Russia is allowed to send a team of 19 officially neutral athletes to the world championships in London after they're vetted by the IAAF. When Mariya Lasitskene wins gold in women's high jump, the Russian anthem isn't played. Two Russian silver medalists later have their IAAF status revoked amid investigations into whether they broke anti-doping rules.

Dec. 2017 — Faced with evidence of mass Russian cheating at the 2014 Winter Olympics, the IOC officially bans Russia from the 2018 Winter Olympics in Pyeongchang. However, it allows 168 Russians to compete as "Olympic Athletes from Russia." They win gold in women's figure skating and men's hockey. Two Russians fail drug tests during the games.

June-July 2018 — Russia hosts the men's soccer World Cup. Before the tournament, soccer body FIFA looks into alleged doping in Russian soccer but doesn't issue any sanctions.

Sept. 2018 — WADA reinstates the Russian anti-doping agency against opposition from many Western athletes, who feel Russia hasn't publicly accepted it cheated. WADA's condition is for Russia to turn over stored data and samples from the Moscow laboratory that could implicate more athletes. Russia misses the initial December deadline but finally hands over the files in Jan. 2019.

Oct. 2018 — U.S. prosecutors allege Russian military intelligence officers hacked sports organizations, including at the 2018 Olympics, as it tried to paint athletes from other countries as cheats.

June 2019 — Former IAAF president Lamine Diack is ordered to stand trial in France over accusations of corruption, including an alleged scheme to cover up failed drug tests in return for payments from athletes. Evidence has emerged suggesting that as much as $3.5 million may have been squeezed out of Russian athletes to hush up their doping.

Sept. 2019 — With four days to go until the track world championships in Doha, Qatar, WADA says it has found signs that the lab data handed over by Russia eight months earlier may have been tampered with. Russia is given three weeks to explain, and the Russian Olympic Committee expresses concern it could be barred from the 2020 Olympics in Tokyo.

___

-sports