Dear Mr. partha sarathy,
I do not find any infirmity in the investigation proceedings. You see it from another angle. The investigating officer /police received certain information and he laid a trap and in the trap, the person was caught. The investigating officer from the spot send the rukka to the police station through a police personnel and on the basis of the rukka, the duty officer at the police station lodge the FIR and send the FIR copy along with the rukka back to the spot for further investigation (which includes recovery of articles, preparation of site plan, recording the statements of the witnesses).
I think I am clear and correct.
Invite the suggestions of other members of this forum.