The Texas law says that you can be charged with Murder if you are fleeing from a felony and cause another person's death by an act clearly dangerous during the commission or flight from the felony. The problem is that they were not committing a felony.
There is Manslaughter and Criminal Negligent Homicide to recklessly or negligently cause a person's death but I have never seen that used unless the person actually caused the death, not merely created the situation. Those two guys didn't do anything personally that killed her death. Of course a DA can do what he wants within the law and if he gets a conviction we might get a new case law. Anytime a prosecutor pushes the envelope on meaning of a law, we have a chance of an appeals court setting a precedent on what the law means or how it is to be applied. I call it stretching the legal rubber band.
A case law might have already been set in situation like this but if so, I am unaware of it. From my past experience in Jefferson County the former DAs have not been big on pushing laws to the limit.