Just a quick update. I spoke with my lawyer friend but her expertise in this area is not specific enough to really help us in this matter. She, as well as the police, have told me this would normally classify as a civil case, relating to the agreement signed between me and Intersango and hence they advised to arrange a consult with a civil lawyer, which is what I think Icicle has already done. Also I don't think a Dutch lawyer can really help here, since the company is based in the UK and Patrick is in the US, so I think for now it may be best to follow Icicle's approach and contribute to her case the best we can.
In response to your comment on being from the first world: 12.4 BTC is a lot of money to me. I am a student and I could currently pay off a good part of my student loans with this (esp together with the BTC that went missing at mtgox), which will save me a lot of worries during for years to come.