Martin "Marty" Martinez had been under investigation since the Oct. 2 death of a toddler whose mother, Dr. Amanda Crews, was among the victims found Saturday afternoon in the Modesto home Martinez used to share with her.
Authorities have not determined a motive or released how the five died, including Martinez's and Crews' 6-month-old daughter, her 6-year-old daughter from another relationship and an unidentified 5-year-old.