Green had been in Cancun before surrendering to U.S. authorities early Friday morning.
Mexico will not extradite prisoners to the United States if they face the death penalty.
The big question for many regarding Jeremy Green's return is, did prosecutors have to take the death penalty off the table to get Green back in San Diego?
Former San Diego District Attorney, Paul Pfingst cleared up the death penalty extradition issue.
Pfingst is not representing Green, but expects defense attorneys to argue the killing was manslaughter, not first degree murder.
Police said Green returned to the United States Voluntarily, and no promises were made regarding the death penalty.