07:45 AM on 09/28/11
If you read the first link, it's really sucky how Kele found out too. He was just walking along the street and found the other three members all walking towards a rehearsal studio, then they all went in together without realising he'd seen them. He took a picture on his phone of them hanging around the studio together because he couldn't quite believe it, which is also in that first link.
I'm sure there's more to it than these stories provide, undoubtedly though.