The Reedley Police Department says this is an important factor in the investigation to get a better understanding of what led up to the shootings.
Police found the bodies of Guadalupe Bonds, Billy Bonds and Darrell Bonds on Saturday at their home on Church and Curtis.
The body of Matthew Bonds was later found at their neighbor's home on Tuesday.
A 17-year-old was arrested for the murders, and his mother and her boyfriend were also arrested and charged with accessory.
Detectives believe the motive involved items stolen from a safe at the Bonds' home.
Reedley Police Chief Joe Garza says some of Billy Bonds' belongings were found at the suspects' house.