On January 16, 2019, Gerald David, 81, and his wife Sharon David, 80, were found shot to death in their home in Washoe Valley, south of Reno, Nevada. Their murders were part of a string of killings that began January 10, 2019, in the Reno area, including Connie Koontz, 56, and Sophia Renken, 74, in Gardnerville.

Investigators linked the cases through stolen property: an Apple Watch taken from Koontz was traced to a Carson City woman who tried to connect it to a digital account, and pawn-shop records tied jewelry from Koontz and a ring belonging to Gerald David to Carson City. Those leads focused attention on 19-year-old Wilber Ernesto Martinez-Guzman, who had done landscaping work for the Davids the previous summer and had stolen a .22-caliber handgun from them on January 4, 2019. Martinez-Guzman was arrested January 19, 2019; authorities say he confessed to the four murders and other crimes and was held without bail on multiple murder and burglary charges.

What additional details about the Davids or their routines might help readers who knew them come forward with information?