just my 2cents

the method looks more like an italian job. in naples they use a similar tactic to rob people. tap the car so they are forced or instinctively they get out of the car and then you're done. It's a similar strategy imo. They lured him out like this. Balcan execution style is probably different more military style (Strax let me know what you think) and i'm not an expert in mexican killings but the few I've read the mexican don't make such a "theatre" they just shoot everything down. This was a planed murder that's for sure imo, the shooter wanted him death. He started to shoot when there was no danger no argument and no fight, he just waited for the right moment.
Who is behind? Boh!?!?!