I will not fault the efforts of the searchers on the ground, but I will fault decisions made those in charge at the time:
Why would the sheriff not call in the State Police before darkness fell. (or at least shortly after darkness fell) I am not familiar with how these small-town and small-county police procedures work in Indiana, but I would think that the State Police would have more resources, such as a helicopter with thermal imaging capabilities to help locate persons in the woods.
Also...statement from the sheriff posted on the IndyChannel timeline is disturbing: "February 14, 12 a.m.: The search for the two missing girls was scaled back around midnight because of the dark. At this point in time, Sheriff Laezenby said they had no reason to believe that the girls were in imminent danger and crews would resume their search in the morning."
http://www.theindychannel.com/news/timeline-13-year-old-girls-go-missing-bodies-found
Gee Whiz! two young girls missing in the cold dark woods for about 8 or 9 hours by that time (12 midnight) and he states that he had "no reason to believe that the girls were in imminent danger." What about hypothermia? Animal attack? Injury from a fall? There would be a whole range of things that could have happened to the 2 girls by that point at midnight. At that point, regardless of whether or not a crime had been committed, these two girls were is danger. And every hour and minute counted.
The girls not answering their phones would be all the more reason to keep up the search. In my opinion, he should have know at that point that he was not dealing with two runaways and something serious had happened to them and he should have called in any and all resources outside of his small department or county sheriff's office that was available to him. This assumes that the info posted by the IndyChannel is correct.