Fresno police Sgt. Jaime Rios said investigators have been unable to contact the children's biological father, Xa Yang.
The children — ages 5 to 12 — were taken from their Fresno home when their mother and stepfather left them alone to go to a grocery store Saturday evening. The mother and stepfather told police when they returned from the store the children — along with their clothes in the home — were gone.
Investigators said they found no signs of forced entry and they don't believe the children are in any danger. They haven't issued an Amber Alert, but are seeking the public's help in locating the father.
Yang has been estranged from the family for three years, Rios said. Investigators believe Yang lives in Sacramento.
The children are: Chee Nou Yang, 12; Cha Meng Yang, 11; Zia Yang, 10; Chue Feng Yang, 8; Zang Yang, 7; Tria Yang, 6; and Tou Ger Yang, 5.
Anyone with information about the children or Yang is asked to call detective Josh Mendizabal at (559) 621-2499 or (559) 621-7000.