From the March 7, 1890 Brooklyn Daily Eagle:

“Moscow–A ghastly tragedy has come to light in this city. A parcel was left at the residence of Prince Dolgoroukoff, which upon examination was found to contain the head of a woman. With the parcel was left a note, bearing no signature, saying: ‘This is our first exploit. We will soon outdo Jack the Ripper.’ It is believed that the woman was killed for betraying Nihilists.”