Hi,
Your case is mostly related with the Turkish Code of Obligations, particularly the provisions of torts(non-contractual) liability (art.41...)and the contractual liability(art.96...).The burden of proof varies regarding the mentioned legal concepts, as in the torts liability the claimant should assume the whole burden to prove the damage,fault of the offender(s)and the causality; while in the cases relied on the contractual liability just the substantiation of the damage is considered adequate by the applicant of compensation. As you may notice the latter opportunity provides more advantageous terms for the claimant, in any case you would better consult a turkish attorney for details.