Yeah, e-raja, you are right. There does need to be a connection that should prove that it is from God. However, what I don't understand is how we would disprove that it is not from God? And also, how would the proof that it is from God look like?
Our Job is not to disprove, if the claim has not been proven. The burden of proof rests on the claim makers in this case those who say this is a miracle and from God.
We can only guess as to what the proof/evidence of the connection with God would look like. And what a lot of people do not notice is that the more a claim resembles the realm of fiction the more difficult it is to imagine what kind of evidence/proof is required to prove it. Because the proponents of these miracles make these claims it is their duty to provide independent, verifiable, objective and falsifiable evidence as these are objective claims.
Also if you wanted to provide atleast some contention, you could ask the claim makers how do they know it was God who sent these miracles. What if it is Satan, Santa, Zues, Thor, Kali etc or anything your mind can come up with who sent these to lead muslim in to thinking their scripture is true when it is far from it. They will then have to disprove that all other possible explanation which have just as much 'evidence' do not exist, to then say God did it and let me tell you that is quite a task.