Not known.
She used the unforgivable curse Avada Kadavra which is the killing curse.
She didn't want anymore of her kids dead.And revenge as Bellatrix just sent a killing curse at Ginny and it JUST missed her.
Bellatrix Lestrange sends a killing curse that misses Ginny by an inch. Molly, who had already lost one child that day, starts dueling with her and kills her.
In the end of the seventh book. She originally goes for bellatrix because she almost hit Ginny with a killing curse and says "not my daughter, you bitch!" it's the best thing ever. :)
Harry Potter has used two unforgivable curses. In the Order of the Phoenix he used the Cruciatus curse on Bellatrix Lestrange, then in the Deathly Hallows he used the Imperius curse to break into Gringotts.
Bellatrix uses the Cruciatus curse, an unforgivable curse, on them, until they turn insane. The Curse causes immense pain. For this act, she, along with her husband, brother-in-law-, and Barty-Crouch Jr are sent to Azkaban.
The Order of the Phoenix only kill Death Eaters who want to kill others, they are protecting people. Molly killed Bellatrix because Bellatrix almost killed Ginny. To cast an unforgivable curse you need to mean it and Molly meant it because Bellatrix has almost killed her daughter and had hurt other family members.
Bellatrix is killed in the final battle in Harry Potter and the Deathly Hallows. She tried to kill Ginny Weasley, so Molly Weasley became furious (as any mother would) and hit her with the killing curse.
Well it depends on what your talking about. there is also a constellation named Bellatrix. but if your talking about the one in harry potter, she was killed by Molly Weasley during the battle of Hogwarts with Lord Voldemort and his death eaters and other creatures that he got to fight on his side in Harry Potter and the deathly hallows part2. to kill Bellatrix, Molly didn't use any unforgivable curse. the spell that she used caused Bellatrix to freeze and become very thin and then explode into a thousand pieces. in my opinion, it was a bad death and a fast one.
Nobody knew about it.
Ginny didn't kill Bellatrix, Molly did. Bellatrix was killed in the Great Hall, although this may change in the movie.
Bellatrix Lestrange was Nymphadora Tonks' aunt. But Tonks' father was muggle-born so the Black family disowned Tonks' mother, Andromeda. Bellatrix hated that her neice made the line unpure and during a battle killed her.