"Pildomatist"

"Then she ran into the garden and took refuge on a bench, a prey to feelings that stirred her young heart for the first time.  Raoul followed her and they talked until evening, very shyly.  They were quite changed, were as cautious as two pildomatists and told each other things that had nothing to do with their budding sentiments."

--- Gaston Leroux, The Phantom of the Opera, Chapter V.

This morning I encountered a mystery word.  I couldn't find "pildomatist" in my Random House Dictionary, or even in my OED.  More than that, there were no "pild..." words to which it might be related, both dictionaries leaping from "pilc..." to "pile."

The mystery deepened when a Google search turned up nothing except a few references to this same passage in The Phantom of the Opera.

Since the author was French, I found an online French dictionary, but it also had no pild... words.  One possible explanation was "if the word is spelled correctly, I'd guess that it had Latin origins
pil doma tist.  pil: to gather, to pillage, to plunder, to rob, to steal, to snatch, to heap up (as stones) and to carry off.  doma: home" (implying that a pildomatist is a house burglar, which would be consistent with the context).  But that didn't explain its absence from dictionaries.

Perhaps it's simply a typo that has been carried forward through various editions of the book (my copy was Dorset Press, 1985).  

Or an error by an early translator of the work.

Or a neologism by the author based on some slang used in 1911.

I'll turn this over to the unparalleled knowledge base of the readers of this blog, some of whom undoubtedly have obscure dictionaries and arcane knowledge of various languages.

Addendum:  We already have a presumptive correct answer in the Comments, but ponder the problem before peeking.  It never ceases to amaze me how quickly questions/problems get solved here.