Because he didn't take Lisa and they know where he was during those hours? Could be he's on video............stealing something besides a baby.
Well, IMHO, that doesn't clear anyone of "involvement" just because they weren't present at the original kidnapping.
I would like to know who vouched for him from 6:40 p.m. to 4 a.m. that is of the character that could be believed.
I mean really. LE almost never openly states they've cleared ANYONE in a case like this, much less this fella.