Legal Question in Family Law in Washington

I'm sorry to read about what happened to your sister. Unfortunately, the law punishes a parent, even one with the best of intentions, such as your sister, when they resort to "self-help." Given the facts that you have related above, if your sister should have both filed the CPS report, which it sounds like she did, and then used that information to pursue a protection order on behalf of the children, which would temporarily award her custody. She would be in pretty good shape then to pursue full custody. Given what has happened, she may still have a case to seek a modification of the current custody orders, so that she could ask the court to switch custody, if that's what she wanted to do, but it will be harder now, given her arrest.

I advise you to tell your sister to seek local counsel because it may not be too late, despite her current predicament. Getting arrested made it much harder, but it doesn't change the fact that the children have been neglected or put in danger when with their biological father, which she may be able to use to her advanatage. Best of luck to your sister.