i m 99% sure dear nd there r many reasons 2 be sure
- shyam calling sum1 wen the family was planning 2 send khushi 2 london nd thn Khushi getting a call about arnav being missing after 3 days
-shyam being restless wen Anjali mentioned police nd then he went away nd they received call from Arnav so it was obvious tht Shyam (if he is really d kidnapper) did'nt want nyone to have a doubt tht Arnav is in sum danger nd inform police
-the kidnapper knows arnav has diabetes nd tht means he knows arnav very closely