'A Van', for the Ukrainians to be responsible 'erroneously' there would need to be some target they actually intended to hit with such a missile. I don't believe there is any credible evidence of any such target, despite eager but absurd suggestions it was aimed at Putin.
A hefty weight of evidence already points to this being a cock-up by separatists. Why fake evidence of an *accidental* shoot-down? Russia's role looks like the old Cold War coat-holding role that CIA types also so often played: archetypally a briefcase full of banknotes and a few greasy spare parts, on the assumption that the beneficiaries of this largesse don't have it in them to screw up so catastrophically that a host of enraged non-ally nations start demanding a full reckoning.