The remains of four bodies were found in shallow graves in the Mojave Desert on Nov. 11 and Nov. 12. Clothing was also found.
The California Department of Justice DNA Lab said the remains are that of 3-year-old Joey and 4-year-old Gianni.
The San Bernardino County Sheriff's Department confirmed Nov. 15 that other remains found in the desert near Victorville were Joseph and Summer McStay.
The family disappeared from their Fallbrook home in February 2010. Relatives were left puzzled. They described the family as happy and living the American dream. The family's dogs were found wandering their backyard, and money was left in their bank accounts.
The family's SUV was found near the border, and at one time, investigators believed the family may have left to Mexico. But relatives did not believe that theory and suspected foul play.
The deaths have been ruled a homicide, but investigators aren't releasing a motive nor are they revealing how the family was killed.
The San Bernardino Sheriff's Department is leading the ongoing investigation, and the FBI is assisting.