You cannot scientifically prove that God did something. You can however prove that an unknown force is acting upon something. Religious people will attribute that force to God, atheists will be satisfied with labeling it an unknown force. You can speculate that it is aliens, or pink unicorns. Throughout history we science has repeatedly discovery a widely accepted explanation for unknowns, the atoms, gravity, bacteria, etc. But for scientists to categorically state that intelligent design can never be the answer to an unknown is trying to prove a negative.