Authorities say Ramirez-Serna killed Justin Robinson in November 2017, dumped his body in a reservoir on the Wyoming Hereford Ranch and burned his SUV.
Lisa Rench and Traquevis Hardy were arrested on May 13, 2018, after Wyoming troopers responding to a REDDI report found drug paraphernalia in their car.
In addition to prison, the Sinks were also ordered to pay over $6.2 million in restitution and to forfeit over $750,000 in assets traceable to the fraud.