Re: "I will die within a year"
Russian efforts to quiet troublesome people aren't limited to their own shores:
In Spanish custody or not, the Ruskies would already have terminated him if that was what they wanted. My guess is that although Levashov is a bottom feeding schmuck, and most of his (reported) stuff is low level fraud, he probably has been taking payments from, or subject to control by fear from Russian intelligence, for the purposes of deniable attacks, or for distributing malware, or for information on his associates. So for preference they'd prefer not to have him plea bargaining with the MIB, and by trying to extradite him themselves, they can pretend that they are interested in stopping their citizens form doing this.