Perception, I assume, to seek any residual leads:
Perception 1d20+15 : 8 + 15, total 23
I'm assuming we have daylight here, else subtract 6 from my roll.
A separate perception for searching the first building I check:
Perception 1d20+13 : 14 + 13, total 27
Unsure if the daylight helps my perception inside this building (there are windows, right?); If not, once again subtract 6. Claustrophobia penalty is already factored in.