Investigators into Gene Hackman and Betsy Arakawa's deaths are shedding light on how the couple's dog, who was also found dead at their New Mexico home on Feb. 26, could have died.

Hackman's cause of death has been determined as hypertensive and atherosclerotic cardiovascular disease with Alzheimer's as a significant contributing factor, officials said in a March 7 press conference. Investigators believe he passed away around Feb. 18 due to the readings on his pacemaker.