One thought, unplug everything associated with that line of plugs. Take a trusted electrical device and plug it in. Perhaps a device on that string is the short, and not the in-wall wiring.
Other than that, as people have said above, you've got a short. Basically, a loose wire that is connecting to some other power draw that is bleeding power off of that line of outlets. Don't mess with it, call an electrician.
The problem is these shorts can get bad enough to start a fire so don't mess.[/QUOTE]
+1
I am no electrician, but this makes sense to me.
Before you do any checking, is the wall in question hot(referencing the bold type)? If so kill the circuit and call an electrician.
If you need to turn of the circuit use one of these to check. This voltage detector flashes to let you know it is on and reading. IMHO the best.
https://www.fluke-direct.com/produc...fC3YkgLTGkuHLRDDmH7DXsJ0aXI8Kqn4aArjpEALw_wcB
If you want to check the wiring of an outlet this can help to check if it's wired correctly:
http://www.all-spec.com/Catalog/Tes...uEa7w2XCEIcJCegmq78IRR0DjYaGjqtYaAha8EALw_wcB
If the structure was built after 1999/ 2002, you might need an arc fault receptical checker.
https://www.toolexperts.com/afci-tr...rnm4Av9yPX4yGYaIDfA6cOL79VIkQ-3saAiWEEALw_wcB
I wouldn't recommend going any further then this, but if you do,
do not check amps with a multimeter even if it is a CAT III or above.
Even this meter should only be used for a short check of 15 to 20 amp circuits. If you are considering investigating this on your own. Read resistance, and voltage, and calculate amps using ohm's law.
http://www.rapidtables.com/electric/ohms-law.htm