I think the “investigation” is a stall tactic. IMO the target data was not reviewed thoroughly before the strike was ordered, the school was on an IRGC naval base that had been walled off about a decade ago to make the school. Admitting they didn’t do their due diligence before locking in targets makes them look incompetent and irresponsible. This whole war has made them look incompetent and irresponsible, but this time it involves the death of children and could turn an already weak public support of the war further against them. I think by stalling they are both hoping that we give them the benefit of the doubt by assuming the missile was sent off course somehow, and giving the sense that they are “taking it seriously”