Sergey Vladimirovich Cherkasov
Sergey Vladimirovich Cherkasov (), also known as Victor Muller Ferreira, is an  alleged Russian intelligence officer working for the GRU, whose true identity was revealed by the Dutch General Intelligence and Security Service in 2022. He was first sentenced by a Brazilian federal court to 15 years in prison for using a forged Brazilian government-issued document, but the sentence was later reduced to 5 years and 2 months. Known background
According to his Russian passport, he was registered as a resident of Kaliningrad exclave; public registry data showed he was a co-owner of a Kaliningrad construction firm at the age of 19. His real age at the time of his arrest in 2022 appears to be 36, while the age of his alias is 33. Cover story
The Dutch Military Intelligence and Security Service published a document in broken Portuguese that they stated was his cover story. The document says that he went to Rio de Janeiro in August 2010 to meet his estranged father, whom he blamed for his problems, as well as for the deaths of his mother and his aunt. The document claimed he had forgotten his Portuguese, and asserted that he had moved to Brasília when he was supposedly 25 years old. He claimed he was in Brazil "to learn the language and restore my citizenship". Some details of this alleged background have been described as implausible. The document further mentions his having to visit Ireland to attend the funeral of his father. Education
According to a CV posted online, he studied political science at Trinity College Dublin from 2014 to 2018 for his first degree, then earned his Master's in a prestigious international relations program at Johns Hopkins University's Paul H. Nitze School of Advanced International Studies (SAIS), majoring in U.S. foreign policy. While pursuing his master's, he was a student of Evgeny Finkel. While studying in Ireland he was known to Irish counter-intelligence. Attempt to enter International Criminal Court
In April 2022 he flew to the Netherlands to take up a position at the International Criminal Court in The Hague. He was detained at Schipol airport by Dutch immigration officials and returned to Brazil. Upon arriving in Brazil, he was arrested for identity fraud and is now serving 15 years. At the time of his hiring, the ICC had begun to investigate war crimes committed by the Russian army in Ukraine. Had he managed to take his ICC position, he would have had access to the ICC email and document systems. Uncovering the spy

It is believed that a discovery made in 2018 in the poisoning of Sergei and Yulia Skripal case, where the Russian GRU suspects were found to have passport numbers that were close to each other, led to an investigation by many countries of historic Russian passport numbers. Cherkasov was discovered by the USA to have a close number, identified and tracked, leading to a tip off to the Netherlands authorities. Reactions to discovery
Eugene Finkel tweeted that the alleged spy was a former student who had claimed "Brazilian/Irish roots" and who had asked him for a reference letter for his application to the ICC. Finkel tweeted "I wrote him a letter. A strong one, in fact. Yes, me. I wrote a reference letter for a GRU officer. I will never get over this fact. I hate everything about GRU, him, this story. I am so glad he was exposed." The Dutch intelligence agency said "The threat posed by this intelligence officer is deemed potentially very high". Donnacha Ó Beacháin, a professor of politics in the School of Law & Government, Dublin City University, said it was not surprising that he was educated in Ireland, but it was, in fact, surprising that he was caught. He added "Essentially these are sleeper agents. The idea would be that - from a young age- they would build up a fake identity, and they would acquire different qualifications and credentials that would make them more plausible. Then they will be used to infiltrate Western organisations. Trinity College would be a very credible university based in a friendly western country. So from that perspective, placing an operative in Trinity and giving them a background there would be something that can be utilised later." Conviction and extradition request 
He was first sentenced by a Brazilian federal court to 15 years in prison for using a forged Brazilian government-issued document, but the sentence was later reduced to 5 years and 2 months. In July 2023, Brazilian authorities have declined a US request to extradite him, saying that he would eventually be sent to Russia instead. In a statement, Brazil’s Ministry of Justice and Public Security said that Brazil’s Federal Supreme Court approved on March 17, 2023 an application to extradite Cherkasov to Russia, where he is accused of “drug trafficking,” according to Russian state-run news agency TASS. In the United States, he was charged on March 24, 2023 for acting as an agent of a foreign power, visa fraud, bank fraud, wire fraud, and other charges stemming from his alleged illegal activities in the United States. References

Living people
People from Kaliningrad Oblast
GRU officers
Russian spies
Russian people imprisoned abroad
Prisoners and detainees of Brazil
Brazil–Russia relations
Brazil–Netherlands relations
Netherlands–Russia relations
Date of birth missing (living people)
Year of birth missing (living people)