[A_D_E_P_T]

Oh, I'm not so sure. Check out the Japanese guy at the link I posted. The Japanese equivalent of the FBI were searching for him like crazy -- his "Wanted" poster was seriously in every subway station across the nation -- and he managed to get away with it. Many such cases. There are lots of wanted men on the Interpol red list, and "state backed intelligence agencies" are actively searching for many of them. Some of them have been on the list for many years.

Intel agencies aren't magic, and they're not omniscient. If you're careful, the best tool they have is facial recognition, like Clearview, but that has yet to reach its full dystopian potential.

In OP, you've got a famous Russian defector who retired to a Russian resort town on the Spanish coast. A very boneheaded move, that; ofc he was going to get caught.