I would be leaning toward drug overdose, if Hayleigh wasn't kidnapped (for real), as the fact that no one called for medical help is telling. A blow to the head, an injury-they can be explained as accidents. A drug overdose? Not so much. The fact that Ron called home so many times, called people to go over and check-indicates he already knew something was wrong. I don't think this was a normal pattern. Even if Misty wasn't home, and discovered a dead child upon her return-I don't think Ron would cover that up. So either she really WAS kidnapped (and Ron may have an idea of who, but now where she is-someone HE is afraid of), or something happened that pointed to their illegal activities and had to be concealed. Not an injury, even caused by fighting with Misty-children fall, they hit their heads...a gun injury or drug overdose would need to be concealed.