An assassin, a computer hacker, and a husband and wife team of sleeper agents were among the prisoners the U.S. and its allies returned to Russian President Vladimir Putin, multiple outlets reported on Thursday.

Earlier in the day, Russia and the United States announced the largest prisoner exchange in the modern era when Wall Street Journal reporter Evan Gershkovich, American Paul Whelan and a number of Russia dissidents were released in exchange for eight Russian detainees.

Vadim Krasikov is a former Russian intelligence agent who was serving a life sentence in a German prison for the 2019 assassination of Chechen rebel Zelimkhan Kangoshivili. Putin had long sought the return of Krasikov and many observers have seen his release as key to the larger exchange. Krasimov has been linked to at least two other murders, notably a Moscow restaurant owner in 2015 and a businessman in the northern European region Karelia, in between Finland and Russia, in 2015.

The Associated Press reported that Krasikov was attempting to escape on an electric scooter after he shot Kangoshivili in a Berlin park. German authorities said Krasikov was acting on orders directly from Moscow and had supplied him with false identification and the resources to perform the execution.

Artem and Anna Dultsev are a Russian couple that had been posing as Argentine citizens and had used Slovenia as their homebase to disperse cash and assignments to fellow Russian sleeper agents throughout the European Union. Artem lived as an IT businessman while Anna posed as an art gallery owner. NBC News reported the two lived under the names of Ludwig Girsch and Maria Rosa Mayer Muños and have two children who attended an international school in Ljubljana, the capital of Slovenia.

Roman Seleznev is the son of Russian parliamentary member and described as "one of the most prolific credit-card thieves in history." Seleznev was captured in the Maldives in 2014 and was sentenced to 27 years for fraud, computer hacking, possession of illegally obtained credit cards and theft of personal data. One of Seleznev's hacking schemes is alleged to have caused $170 million in damages following the sale of stolen credit card data from American stores and restaurants.

While the Biden Administration praised their negotiating skills and the release of the prisoners, former President Donald Trump was less complimentary saying, "I got back many hostages, and gave the opposing Country NOTHING."

Russian news agencies quoted Putin as saying the eight detainees would all be given state awards and told them that Russia "had not forgotten them, not for a single minutes," Reuters reported.

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