After reading "BB murder case
" I was surprised why I didn't put everything together.
There are some clues pointed out that Beyond Birthday was featured in the anime. You just never saw his face.
Yomi kun sent me this video showing B.B. at the Wammy's House. No this is not an edited scene. This really happened.
I'm such an idiot! How could I not have known this!
In the manga it was Matt, however in this clip it's B.B.