Why?
In my opinion, the reason is not far to seek.

The Earl of Valletort and Count Ladislas Vassilan were crossing the Atlantic hot in pursuit of the unwilling bride.

They arrived in New York to-night, and were so well posted in events, both past and prospective, that they headed straight for the flat in which Lady Hermione was living with her maid.
Naturally, I am keenly interested in the causes which led up to a peculiarly brutal and uncalled-for murder, and, as my wife's husband, I have the further incentive of hoping to bring to justice certain of her persecutors whom I cannot help connecting indirectly with the crime of which I was, I suppose, one of the most credible and intelligent witnesses.

Now, before I was aware that such a winsome creature existed as the present Lady Hermione Curtis, I had estimated the murderers as Hungarians, two of them at any rate, since I am hardly prepared to vouch for the chauffeur.

Count Ladislas Vassilan is a Hungarian.