"You're lying, you filthy Mudblood, and I know it! You have been inside my vault at Gringotts! Tell the truth, tell the truth! What else did you take? What else have you got? Tell me the truth or, I swear, I shall run you through with this knife! What else did you take, what else? ANSWER ME! CRUCIO!"

Skirmish at Malfoy Manor

In 1998, when Harry Potter, Ron Weasley and Hermione Granger were captured by Snatchers and brought to the Manor with the real sword, Bellatrix panicked. This led to Harry thinking that there could be something else of Voldemort's in her vault — his Horcrux, Helga Hufflepuff's Cup, seeming most likely. Bellatrix Stunned all the Snatchers, intending to kill them later, as Draco was unwilling to himself.

Bellatrix then interrogated Hermione and tortured her with her knife, slitting her arm while carving "mudblood" into it and torturing her by making the cut grow bigger every second, but Hermione managed to lie under unbearable pain, claiming the real sword was only a copy, even if it meant torture.She thought that maybe Harry and his friends got the Horcrux from her vault, so she told Peter Pettigrew to get Griphook from the cellar to tell her if the sword was fake or not. Griphook managed to tell a lie, obeying Harry's request to him and keeping their secret safe.