Which preposition to use with dossier

of Occurrences 4%

* Dawson led me to the private office at the Central Police Station, which was his temporary headquarters, and sent for the dossier of the locked up draughtsman.

in Occurrences 1%

Though the major was reluctantly forced to admit that our papers were in order, we were nevertheless sent to staff headquarters in Antwerp guarded by two gendarmes, one of whom was the bearer of a dossier in which it was gravely recited that Captain Briggs and I had been arrested while in the company of a person calling himself Donald Thompson, who was charged by the chief of staff with having smiled and smoked a cigar in his presence.

Which preposition to use with  dossier