From time to time there are scraps of news in the Civil & Military Gazette I find truly surprising or weird. Here is an account apparently of human sacrifice (though actually it appears to be two separate incidents, narrated here together.)
I don't know the history of this -- or the possibility that British authorities might have been misinterpreting the deaths described in the Civil & Military Gazette in a short news scrap on February 5, 1886:
Kali is one of the Hindu deities western anthropologists have long used as evidence of the "savage" underside in Hindu ritual. As recently as 2010 there were stories in the Indian media about a possible human sacrifice near Kolkata, and there was an extensive article in Time in 2002 that essentially took it for granted that these sacrifices still occur on a regular basis. The Time article is a little short on specifics, however, and I'm inclined to take its premises with a grain of salt.
A quick search of Books.Google only affirms that the British seemed pretty confident that they were responsible for stopping regular human sacrifices at Kali temples. See this account from 1914, for example. But recent scholars who have worked on Tantra or Kali (such as Jeffrey Kripal) have largely not mentioned this, and I'm not sure why. Is it because they find it obvious that this didn't occur, and don't feel the need to address an old, self-serving British myth about Hinduism? Or is it because they presume that the British colonial accounts were correct, but would rather not dwell on this aspect of Kali worship?
I do not know of any Hindu sources that confirm this practice. There is a fair amount of corroboration between the British sources (the account in the link above, from 1914, also names Bastar, for instance, as a place where human sacrifices had recently occurred). Several sources all seem to confirm the story that human sacrifices occurred "every Friday" until the British "put a stop to it" in the 1830s, but it's possible this is simply the recirculation of a myth taken as fact without any actual archeological evidence.