If neither parent has custody can the father take their child to live with him and it not be a crime so long as he files a parenting plan and they both live in Washington state?

Answer

Do it the legal way and have her served. You will need to file the proper custody paperwork at the courthouse, then wait until she is served. Once she has been served, take the children legally. Get a lawyer and be prepared for a fight.

Yes. Until a custody order has been issued by the court both parents have full rights to their biological child/children. The other parent must be notified of the child's/children's whereabouts and be allowed reasonable visitation. Likewise, as noted, in Washington State the filing of a parenting plan is usually required. As long as the proper procedures are followed the court will not look unfavorably upon either parent. However, it is not in the child's/children's best interest to be removed from the family home unless the circumstances are such that their well-being is in jeopardy.