Not sure what an electrical pen is, I prefer to use a multi-meter type device, that checks for continuity, AC or DC voltage and gives the amount of each. You say that there is a current, but no mention of how much. Sounds like you have a back feed from somewhere in the circuit. The odds are that the hall and bedrooms are all on the same circuit, which shouldn't be, but in older homes it happened more often than it should, especially if the homeowner does the wiring. It's also possible that there is one or two outlets that have loose or broken wires going to them. I've seen it happen more than once, and while it 's not fun finding it, it can be done. Best advice would be to get a qualified electrician in for a look-see. It would probably be worth the money. By the way, Stanley, I've worked on hundreds of homes, electrical systems, taught electrical in 4-H for years, and have never heard of outlets being wired in series. That would make no sense at all. Outlets are wired in paralell.