Where would LE search?? I imagine they are pouring over Caseys cell phone activity and credit card activity to figure out where the liar has been for the last months. For all we know, Casey could have been in Texas, Ohio, Calif., Tennessee, Maine....etc., etc.
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I agree, conducting large ramdon searches for a missing 3 year old to me doens't make sense. If the child really did just wander away from pre school or something, then it would make sense to canvas the whole area.
But, no one even knows when she disappeared, what week, from what location, there is a MONTH LONG period of time that her whereabouts can't be accounted for. The only way to find a reasonable place to search is to reconstruct WHERE Casey was and go from there.