The deaths took place sometime between Thursday afternoon and evening by someone who had some type of relationship with the victims, the Oneida County Sheriff's Office said. The bodies were discovered Friday outside Holbrook, a town of about 400 people just north of the Idaho-Utah state line.
Authorities said a 2-month-old was found under the arm of one of the victims—27-year-old Yavette Chivon Carter. A 2-year-old was also found unharmed and both children have been turned over to relatives.
About 70 pit bulls were also found. Police said the dogs were being raised for sale and for fighting.
The other two victims were identified Saturday as 61-year-old Brent L. Christensen and 32-year-old Trent Jon Christensen. Oneida County Sheriff Jeff Semrad told the Idaho State Journal the victims are a father, his son and the son's girlfriend.
Sheriff's officials were looking to contact people who attended a party at the home on March 31.