If Adam had access to the house at 6:30AM on 7/13 then why wouldn't he have had access at 3:00 AM of the same morning. Did Rebecca or Jonah give him a key to get in after 3:00AM but before 6:30AM?
Who said he had a key ever? There is no evidence Adam wanted or tried to access the house prior to his discovery of RZ's body. No evidence he was ever given a key by anyone. LE haven't said he had a key to the main dwelling. You are asking me to speculate on something that has never been raised as an issue by LE. THEY know the time the computer was accessed and they know who had access to the house.
JMO