The Somali pirates were convicted earlier this month of shooting Bob Riggle and Phylis Macay of Seattle and Jean and Scott Adam of Marina Del Rey, California. The couples were sailing in the Indian Ocean on the Adams' yacht, the Quest, when the vessel was hijacked by the pirates in February 2011.
The sentencing hearing for the Somali nationals is taking place this week in a Virginia courtroom, and could stretch into early next week.
Eleven other Somalis involved in the incident have pleaded guilty and are serving life sentences.
Riggle and Macay were experienced sailors who met at the Seattle Singles Yacht Club.
Over the last few year, the number of pirate attacks has dropped significantly. One reason for this might be the fact more ships traveling in that part of the world now have armed guards.
A recent report from the United Nations suggests pirates are moving into the business of providing private security for unlicensed fishing vessels in Somali waters.