LinkedIn said that the arrest, was carried out in cooperation with the FBI:
''Following the 2012 breach of LinkedIn member information, we have remained actively involved with the FBI's case to pursue those responsible. We are thankful for the hard work and dedication of the FBI in its efforts to locate and capture the parties believed to be responsible for this criminal activity."
The bloke in question is Yevgeniy N, born in 1987, who was arrested at a central Prague hotel on 5 October in response to a "red notice" issued by Interpol and could face extradition to the US.
What is rather strange is the Russian state news agency Tass quoted Andrei Kolmakov, a spokesman for the Russian embassy in Prague, as saying it insists that the hacker be handed over to them.
"The embassy has been taking all necessary efforts to protect the interests of this Russian citizen. We are in contact with his attorney. Russia repudiates Washington's policy of imposing its extraterritorial jurisdiction on all countries. We insist that the detainee is handed over to Russia."
We assume this is so that he can get back to work.
The FBI said that the man was "suspected of conducting criminal activities targeting US interests," but did not provide any further details. Two US law enforcement officials told Reuters that the new arrest is not related to the recent hacks of the Democratic National Committee or other political organisations that Washington recently accused Russia of orchestrating in an attempt to interfere in the upcoming 8 November presidential election.
Russian President Vladimir Putin has denied any involvement by the Russian government in the cyberattacks.
In May, LinkedIn confirmed that the much-publicised mega data breach in 2012 compromised more user accounts than previously thought, urging millions of users to reset their passwords and enable two-step verification. At the time of the hack, it reported that 6.5 million email and password combinations were compromised.
The stolen user credentials were put up for sale on the Dark Web earlier this year by a hacker going by the name "Peace."