Both deaths were ruled to be from natural causes, chief medical examiner Dr Heather Jarrell said.
Hackman’s death was tied to heart disease with Alzheimer’s disease contributing.
Authorities linked Arakawa’s death to hantavirus pulmonary syndrome, a rare but potentially fatal disease spread by the droppings of infected rodents.
Hackman’s pacemaker showed an abnormal heart rhythm on February 18 — the day he likely died, Jarrell said.
While there’s no reliable way to know for sure when each died, all signs point to their deaths coming a week apart, Jarrell said.
Hackman’s body was found in the home’s entryway, and Arakawa’s body was found in a bathroom.