Didn't they hire a bunch of new people in last few years to work for IRS?
Yes, they did.
They can always find someone who is living in different countries around the world and pay them much less to help them to arrest anyone they want.
No, they can't. You have to be a US citizen to be an IRS agent as they are government employees. Its not a call center or something. They work in tandem with law enforcement / government officials around the globe, and the US doesn't pay them for that. Like I said earlier, extradition treaties are a two-way street: if Spain requested a known criminal living in the US to be extradited, the US would help them with that as well.
No need to spend so much money for traveling as person being arrested is going to be held in foreign prison first
Its far more complicated than that.
like Roger is held in the same prison like John McAfee was... what a ''coincidence''.
Well they both went to Spain.