No. They should be tried, convicted and sentenced where the crime took place.
Why push off there prison tab onto the AMERICIAN tax payers?
Simple answer is they should be deported.
Because it doesn't have much of a deterrent effect. Think about it...if you were an illegal immigrant, would you fear going to prison for 20 years or being sent back to Mexico more?
And besides that, who can guarantee that he won't get a slap on the wrist back home, where he might be seen as a victim of the "Big Bad Americans".