After losing to Russian swimmers in two races at the Olympics, American backstroke star Ryan Murphy said that doping remains a huge problem in the sport and he wonders if all his competitors are clean.

Murphy returned to the US this week and spoke from his home in Berkeley, California.

Seeming to take aim at a country that has repeatedly run afoul of doping rules, Murphy revealed his frustration after taking the silver medal behind Evgeny Rylov in the 200-meter backstroke.

That came three days after Murphy, who swept the backstroke events at the 2016 Rio Games, settled for a bronze in the 100 back.

In that race, he touched after both Rylov and another Russian, Kliment Kolesnikov.

But later, at a news conference with fellow medalists Rylov, Murphy said he was not accusing the Russian of doping.

Rylov, who has long been one of the world’s top backstrokers, denied being involved in any doping schemes.

Russia has been the most prominent target of the anti-doping movement after revelations that it launched a massive state-sponsored program to elude testers ahead of the 2014 Sochi Winter Games.

The country was forced to send depleted squads to the last two Olympics, and those that did compete at the 2018 Pyeongchang Winter Games were referred to as OAR, Olympic Athletes From Russia.

Then, just when Russia appeared to be patching up its relationship with the rest of the world, more anomalies emerged from the files at Moscow’s anti-doping lab.

Investigators from the World Anti-Doping Agency found evidence had been deleted and spurious information added, including fake messages designed to tarnish the name of WADA’s star witness, former lab director Grigory Rodchenkov.

The new revelations resulted in a four-year sanction against the country, but Russia denied any wrongdoing and the penalty was cut in half by the Court of Arbitration for Sport.

After Murphy’s comments, the Russian Olympic Committee issued a scathing statement on social media saying their country was the victim of “English-language propaganda” spread by “athletes offended by defeats.”

New FINA president Husain Al-Musallam, who took office two months ago, has said that weeding out dopers is one of his top priorities.

The organization insisted that its out-of-competition testing procedures were “in line with that for Rio 2016, despite the restrictions caused by the pandemic.”

Most Russian athletes were allowed to compete at Tokyo, even though they officially represent the Russian Olympic Committee, not their country.

Critics have pointed out that the punishment lacks any real bite, since Russian teams are wearing full national colors.

Their flag is banned and their national anthem can’t be played during medal ceremonies, but they do get music from Russian composer Tchaikovsky.

Two Russian swimmers, Alexandr Kudashev and Veronika Andrusenko, were initially banned from competing in Tokyo by world governing body FINA because of evidence gathered from the Moscow lab.

But, just days before the opening ceremony, CAS cleared both swimmers to take part in the Olympics. Neither won a medal.