LONDON (AP) — One of the two suspects in the poisoning of a Russian ex-spy in England is a medical doctor in Russian military intelligence who was honored as a Hero of the Russian Federation by President Vladimir Putin in 2014, a group of British investigators said Tuesday.

British police say two GRU agents traveling under the aliases Alexander Petrov and Ruslan Borishov used a Soviet-made nerve agent to poison Sergei Skripal and his daughter in the English city of Salisbury in March.

Investigative organization Bellingcat said it had used documents and other research to identify Petrov as Dr. Alexander Mishkin, a member of Russia’s GRU intelligence agency. Last month, it said that Borishov’s real identity is GRU Col. Anatoly Chepiga.

British authorities don’t dispute the identifications. Moscow, which denies involvement in the poisoning, declined to comment.

Bellingcat is a team of volunteer digital detectives who scour social media and open-source records to investigate crimes. In the past, the group has focused on the downing of a Malaysian airliner over Ukraine and chemical attacks in Syria.

The group said it identified Mishkin through passport information, residents’ databases, car registration records and phone records, as well as personal testimony from people who know him.

Mishkin was born in 1979, grew up in the remote marshland village of Loyga in northern Russia and studied medicine at the elite Military Medical Academy in St. Petersburg, according to the group.

Two former students at the academy confirmed Mishkin was the man British authorities identified as Alexander Petrov, Bellingcat said. Bellingcat founder Eliot Higgins said one ex-student told the group that classmates had “been told not to talk to anyone about his identity.”

Seven residents of Loyga visited by the Insider, Bellingcat’s Russian partner organization, also identified Mishkin, the group said.

“They confirmed that their homeboy Alexander Mishkin was the person who moved on to military school and then became a famous military doctor and who received the award of Hero of the Russian Federation personally from President Putin,” Bellingcat investigator Christo Grozev said during a news conference at Britain’s Parliament.

Traveling under his assumed name of Petrov, Mishkin went to Ukraine and other former Soviet states between 2011 and 2013, Bellingcat said.

In 2014, he was active in military operations in eastern Ukraine, where pro-Russia separatists lead a violent breakaway movement. The same year, he was given Russia’s highest honor.

Grozev said villagers recounted that Mishkin’s grandmother had a photograph “that has been seen by everybody in the village, of Putin shaking Mishkin’s hand and giving him the award.”

Putin’s spokesman, Dmitry Peskov, said the Kremlin wouldn’t discuss investigative reports and media articles on the Skripal poisoning. He reiterated Tuesday the government’s claim that Britain had stonewalled Russian requests to share details of the probe.

Skripal, a Russian military intelligence officer turned double agent for Britain, and his visiting daughter spent weeks in critical condition after the Salisbury attack. In June, two area residents who apparently came across a discarded vial that contained the poison fell ill; one of them died.

Britain claims the poisoning was authorized at a senior level of the Russian state — a claim Moscow denies. The Skripals’ poisoning ignited a diplomatic confrontation in which hundreds of envoys were expelled by both Russia and Western nations.

Last month, the two suspects appeared on Russian television and claimed they had visited Salisbury as tourists to see the city’s famous cathedral, only to be thwarted by slush and snow.

Higgins noted that Mishkin’s home village is snowbound for much of the year.

“So his claim that he couldn’t walk through the slush in Salisbury to get to the cathedral seems rather ridiculous at this point,” he said.

The attack on the Skripals has focused global attention on the GRU, an intelligence unit that Western officials say is linked to computer hacking and other covert operations around the world.

British, Dutch and U.S. officials have accused the GRU of trying to hack the computers of international agencies, masterminding a devastating 2017 cyberattack on Ukraine and being behind stolen emails that roiled the 2016 U.S. presidential election.

Last week, authorities in the Netherlands alleged that the GRU had tried and failed to hack the world’s chemical weapons watchdog, the Organization for the Prohibition of Chemical Weapons.

The U.S. Justice Department also charged seven GRU officers in an alleged international hacking rampage that targeted more than 250 athletes, a Pennsylvania-based nuclear energy company, a Swiss chemical laboratory and the chemical weapons watchdog.

Conservative lawmaker Bob Seely, a member of the British Parliament’s foreign affairs committee, said that despite the botched Skripal assassination and failed Dutch hacking, the GRU was a formidable organization, used by Moscow as “the Kremlin’s one-stop shop for global subversion.”

“One shouldn’t just judge the GRU by their failures, because they have had many successes as well,” Seely said. “I think the last couple of operations have failed, but maybe that’s due to overstretch or over-ambition on their part.”