(CNN) A young Russian alleged to have masterminded a massive hacking of social networks including LinkedIn and Dropbox is now at the center of an extradition struggle between the United States and Russia. Yevgeniy Nikulin was detained in October 2016, in the Czech Republic capital of Prague, after US authorities issued an international arrest warrant for him. He was on vacation there with his girlfriend. A grand jury indictment filed in 2016 in California charges him with computer intrusion and aggravated identity theft, among other offenses. Nikulin denies all the charges. If convicted of all charges, he could face a maximum sentence of more than 50 years in prison and more than $2 million in fines.Yevgeniy Nikulin sits in a Czech prison as the US and Russia both seek to extradite himThe alleged computer hacker appeared to enjoy a lavish lifestyle before his arrest 
 Question:The Nikulin case is yet another strain on _-Russian relations.
United States