There's a difference between "think" and "know". I think the probability skews towards Brad being guilty but I don't know this. As far as I'm concerned he is innocent until proven guilty but in saying that I reserve my right to have an opinion - an opinion that may change as more information...
All a familial link does is show that there is a close DNA match and depending on how much of the profile matches determines how likely a family member could be the perp. I read a case recently where police got a familial DNA red flag (let's call it red flag because it's not actually a match...