Emergency Modification of Custody

My question involves a child custody case from the State of: Texas

My 16 year old daughter has came to visit me this summer and now wants to live with me instead of her mother. She has also informed me that there was an incidient in May 2012 where her mother was arrested for physicall violence towards my daughter. CPS was involved, a case was open, and no signs of abuse were found. However, the police report states differently, that the mom phsically hit the child 3 times in the face and pulled her hair. CPS told me they sent a letter to my most recent address on file, but I never received. My daughter has told me about a another incident this last May where her mom chocked her, but didn't report. Do I have grounds for an emergency modification of custody?

The kicker here is that the original custody order was done here in Texas, but my daughter and mom have been living the Washington State for the past 4 years. Can I even pursue this in Texas still?

You titled this as being about an "emergency", but reference an incident that you allege to have occurred more than a year ago. You appear to be telling us that, whatever your child stated to the police, the investigation resulted in a finding that the allegations were unfounded and that no further action should be taken. It is not clear whether you are telling us that you knew of the allegations and investigation at the time, or if your child for some reason chose not to disclose any of this to you until the past week or so. Is there actually something more you meant to tell us, that you believe to constitute an emergency?

If the most recent custody order was issued in Texas, then Texas would have continuing exclusive jurisdiction over the case. That's not a guarantee that, if Texas continues to hold exclusive, continuing jurisdiction, that it won't find that Washington State is a more appropriate venue for litigating a custody case given the amount of time the child has been domiciled in that state.