(Vancouver, WA)  --  Police are searching for a missing 4-year-old girl they think may be with her non-custodial mother.  The Vancouver Police Department says Arianna "Faith" Vaughn went missing after a visitation with her 33-year-old mother Anna Harrington last Tuesday through Saturday.  Police say Harrington never showed up to return Vaughn to her custodial guardian over the weekend.  Anyone with information is urged to contact police.