Where did you hear this? Nowhere has he or Nupur said anything like this. Their arrest was by Noida police on suspicion, since they were at home, and later they found Hemraj's body on the terrace.
Noida police must be asked to teach "HOW NOT TO INVESTIGATE A MURDER CASE". Looks like CBI is equally competent in this task, going by how both have handled the Nithari case so far.
