D.M.
Does she have any type of reflux or ear problems? A friend of mine was going through this and it took a long time to diagnose. What they ended up doing was putting the baby to sleep in the car seat and putting that in the crib. It seemed to instantly help the child sleep better and stop the crying. The position of the car seat kept the childs head elevated enough that the baby didn't have anymore reflux or ear problems. I would say give this a try. What do you have to lose.