Who killed this Harry Potter character?

Question

In Chapter Thirty-One of Harry Potter and the Deathly Hallows,

Fred

dies due to an "explosion" by someone. However, I haven't been able to determine who exactly it was that caused his death. Here's the relevant extract from the chapter:

“You actually are joking, Perce. . . . I don’t think I’ve heard you joke since you were —”

The air exploded. They had been grouped together, Harry, Ron, Hermione, Fred, and Percy, the two Death Eaters at their feet, one Stunned, the other Transfigured; and in that fragment of a moment, when danger seemed temporarily at bay, the world was rent apart.
^{-Harry Potter and the Deathly Hallows, Chapter Thirty-One (The Battle of Hogwarts).}

Is there any evidence or additional commentary to determine who killed

Fred Weasley

?

Answer 1

Unknown, but there's evidence supporting both Rookwood and Bellatrix.

Fred dies due to an explosion of unknown origin, as shown by the quote in your question. We're never told exactly who caused this explosion, so the short answer is we don't know.

However, shortly afterwards, we have this:

he saw many people running backwards and forwards, whether friends or foes he could not tell. Rounding the corner, Percy let out a bull-like roar, "ROOKWOOD!" and sprinted off in the direction of a tall man, who was pursuing a couple of students.

_{-- HP and the Deathly Hallows, Chapter 32: The Elder Wand}

Now Percy has been involved in the Ministry, so it's possible he'd had experience of Rookwood there and had some particular strong reason to dislike him already. But his reaction seems very strong, towards a man he probably hadn't seen for weeks before this day. And he's just lost a brother, which is obviously fresh and raw in his mind. Revenge for that loss would certainly be a strong motivator.

Then a few chapters later on, we have this:

"What will happen to your children when I've killed you?" taunted Bellatrix, as mad as her master, capering as Molly's curses danced around her. "When Mummy's gone the same way as Freddie?"

"You - will - never - touch - our - children - again!" screamed Mrs Weasley.

_{-- HP and the Deathly Hallows, Chapter 36: The Flaw in the Plan}

Again it's not conclusive evidence, since "going the same way as Freddie" could refer to being killed by Bellatrix or just to being killed, full stop. But then, how could Bellatrix even know about Fred? The death of a single young man is hardly noteworthy in that night of horrors, unless you either knew him personally (like his family, Harry, and so on) or were the one who killed him. Why would Random Death Eater feel the need to tell Bellatrix Lestrange that he'd killed Fred Weasley?

And Molly's words also seem to suggest Bellatrix was responsible for Fred. True, she's fighting Bellatrix because the latter tried to curse Ginny, but she didn't actually touch Ginny, so the question remains of what she meant by "touch our children again". Of course, we can't expect pedantry and careful choosing of words in the heat of battle, so perhaps Molly just mis-spoke slightly. Alternatively, "our" could be more general, referring not just to herself and her husband but to everyone opposing Voldemort, all the victims of people like Bellatrix, all those who'd lost children in this war.

Answer 2

It is impossible to know, they were in a battle with magic spells flying everywhere, an explosion could have been caused by a death eater aiming at them (unlikely, they were meant to take Harry alive). A death eater who missed his/her target. An ally who missed his/her target. A giant smashing through something explosive. No one knows who fired the shot. Also the explosion probably didn't kill Fred, After all the others survived. It was more likely a wall/floor that killed him.