in canon he always knew Peter was alive ... just didn't know he was that close to Harry till he saw the paper
Sirius continues "I went to Peter's apartment thinking he was hurt or was being tortured but I found him leaving it in a hurry and that's how I figured he betrayed us so I yelled at him and chase him down but the bloody coward blew up some gas lines with a bombarda, I was able to shield my self but the explosion killed a few muggles and sent me flying, all I could see was Peter cutting off a finger, turn into a rat and get away, I was pretty hysterical and so out of it from the explosion so all I remember was being arrested and the next morning I woke up here".
Book&Literature · Kurogano
he pulled an Anos Voldigoad?!?
"I don't cut loose often, but when I do those that are my enemy...learn to not piss me off.", I growled, "Now I suggest that you prepare yourself, attempting to kill my parents, butler, and my future harem members comes at a very steep price. Ten deaths should be satisfactory before I turn you over to Section 13."
Superman in the Multiverse (MHA, DC, and Marvel)
Anime & Comics · ManOfCultureLeon