The Pelosi residence has top notch security systems, as well as private security, and even if Nancy is in Europe, there should be Secret Service there at all times.
The alarms hadn't been tripped, and there was no notifications by the security systems or personnel.
There are some interesting theories, that Depape had been freely invited in, which could make sense, given the series of events.
Then, you wonder why Google is censoring a lot of content on this developing story...