All of the signs definitely point to some kind of use... I've never taken steroids but I've taken plenty of supplements throughout my time, and I've hit the gym pretty hard as well during that time, and the most I've gained in the shortest period of time was about 13 lbs in 3 months. That was using a lot of creatine, protein shakes daily, protein granola bars for snacks, eating nothing but vegetables and meat - fish oils and vitamins, and using NO(nitric oxide) supplements on occasion while working out twice a day.
And I only kept on a 3 month cycle simply because its said that if you don't cycle the supplements lose their effectiveness.... but I ended up stopping anyway because living like that is torture.
I could see if someone was more dedicated than me... they could do 30 lbs in 6 months.... I had a buddy who was into steroid use.. he did have a lot of body acne, and he bulked up really awkwardly.. biceps, check, shoulders and neck were very big.. everything else looked pretty much the same. That could just be an imbalanced workout habit... but still....