Here's my current working theory on how we got to today: RL's alibi suddenly doesn't look so solid, so they get him on a minor probation violation (maybe even on obstruction for giving a false alibi) that allows them to hold him for 15 days. In a WTHR interview from RL's property today, Sgt. Kim Riley again used the "untrue alibi" type line when asked why they were there, so that seems to be about RL.
While in custody, RL said something--either inadvertently or in attempt to explain why he wasn't truthful before--that gave them PC to search his property. The WIBC story I posted in the last thread made clear it was the Carroll County Sheriff's office who uncovered the new development--not ISP or FBI, so it would seem the PC wasn't the result of analysis of existing evidence like DNA, fibers, etc. In fact, IMO, it is their hope is to get more of that type of evidence with this search, rather than them looking to find matches to what they already have.
This seems to be backed up by the fact that RL didn't seem to clam up with LE until very recently. While we can't know for sure, IMO, it was just in the last day or so. Reporters have been asking LE about RL since he was arrested, but it was only today that the lawyer put out a statement that said he didn't do it. And while that is certainly because they searched his property, I can't imagine the lawyer wouldn't have wanted to clear it up with press as soon as he was arrested and questions were being asked--unless something was said in last few days by RL that led to the warrant, and RL becoming uncooperative.
Now, you real experts can poke holes in my theory.