That was actually the original plan. Well, he did end up knitting for Harry (of course. Knitting godfather, this is my new headcanon), but then the story got more dept to it all on its own. It's amazing how some characters just write themselves sometimes, and Sirius... he always has his reasons. Sometimes he even cares to share them with me. How generous! ;)

I guess everyone suspected everyone, and really, Sirius thought the same of him, didn't he? My theory is that they - despite knowing better - simply jumped to the worst conclusions. And with Remus being a werewolf, and Sirius being a Black... They didn't want to fall back on prejudice like that, it's against their nature, but war does terrible things to you. This proves it.

Thank you!