The hit with a blunt object on the head of Aurishi was so hard that the skull bone caved in , (according postmortem)and it was a gory death for that poor little kid.
They need not have slit her throat as well.
Anyway the killers only wanted to make it sure or it may be that by slitting her throat the killer might have got satisfaction. Read criminal psychology. Criminal's thinking is quite different from normal people.
It may be that her room was poorly lit when she was killed. The way she was killed also shows sexual passion according to the crime profilers and this has been repeatedly mentioned in the media.
The killer might have thought that concealing the weapon would be enough to cover up the crime .
It is also true that these servants would have thought that next morning they would come back to (and they have to ) the house while parents would be weeping and they can clean up if anything left. Or they simply left in an inebriated condition under alcohol. Noida police stupid investigation only helped them. CBI might have already confiscated the murder weapon and cell phones along with other "surpising" evedence etc., Otherwise they would not have come this far perticularly because media attention in this case is almost suffocating.
