Student or Learner
"The massive media coverage would send them further to ground. Also, they would have no obvious connection with the powers-that-be; they were pretty much a dead end."
Those "them" and "they" are some hired hands who kidnaps a baby. An investigator thinks it's impossible they would lead him to anywhere.
Does that expression mean "to hide" or what?
to send them further underground, perhaps, making them even more difficult to find.