There's lots of "mundane" ways to trace people (and you'd be amazed how
often players in such settings tend to overlook them...)  If the kidnapper
uses a cell phone, that can be tracked (with the right authority or skills).
Does he use credit cards?  Track _them_.  (The disguise may actually _help_
this!  Check the sort of places where its elements may have been obtained,
go through their records, and compare.  Even if he/she/it is using a stolen
card, you can still trace that person's movements if they use the card
enough...)  Vehicles can be traced and tracked, too, even stolen ones (which
will attract attention anyway).

Paranormal means can increase the possibilities exponentially.  You mention
a dark room, but what about sound?  Perhaps there are distinctive noises in
the background, like from construction or other heavy equipment.  More
blatant means (Illuminate Trail of Prey or its equivalent) are obvious, but
I presume either the PCs don't have access to them or the kidnapper has
effective countermeasures.  Plus using unconventional means to augment
conventional methods (Dominate to compel cooperation with files or tracing,
Auspex to pick up otherwise missable clues, etc.) can make for a very potent
tracker, even at relatively weak levels!

Don't underestimate contacts.  Putting word out through the grapevine for
people looking like X with a child looking like Y exhibiting questionable
behavior can get a response even from the really hardened types, if only
because having the new Jeff Dahmer move into your neighborhood won't sit
well with darn near anyone...

   ---Doc---
GURPS fan - GMAST-L Old One (once banished)
Philosopher - Alternate Historian - General Crank
email: bravado@mindspring.com
web: http://www.mindspring.com//~bravado

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