Even if he WAS out there "searching" every day, it could simply be as a cover up. We do not yet know what we do not yet know and must consider EVERY possibility. Remember that IF he committed a heinous crime that disappeared the kids, he is fighting for his life.How do we know he wasn’t out there day after day, already searching every square inch of the same area the cadaver dogs later covered. Would be expect they’d find anything, if he didn’t?
Although i have zero firm conviction (because we just don't know), my first thought on his claim of frantically wading through culverts and mud before searchers arrived was it could easily muddle evidence and/or accoint for wet muddied clothing from much earlier than he said. Might, might not. Every possibility must be considered. Its an ongoing investigation.