Plea in murder of BP Agent Terry, with Fast & Furious gun
Another perp involved has taken a plea to 30 years' imprisonment. Another perp also got 30 years, and the guy who bought the guns got under five years.
These are all quite lenient. The gunmen faced the death penalty, and the gun buyer could probably have, too (aiding and abetting the murder makes him guilty of murder). If prosecuted under Arizona law (and they still could be, since the offense broke both State and Federal law), they'd be very likely to get death, and at the very least to get life without parole ("natural life"). I've seen killers get the latter for a single murder and one not committed in the course of a plan for violent criminal acts.