So you still need to figure out WHO had the NEED to do it, i.e the motive, and WHO had the human resources to do it. To me, the real question is…..who benefited specifically? Shareholders? Power brokers? Bankers? You get the drift.
From what I heard in that interview, it sounds to me by Putin's remarks, that one of the intended consequences of bombing the pipeline, was to hurt Russia economically. Take potential rubles out of their hands. Although, it could have been a strategic economic thing, in other words, by allowing Russia to have an impact on their economy through the dependency on their pipeline, they may have felt it unwise or fraught with potential future concerns. I dunno. World politics is full of shitheads on all sides.