Hello,

Forensic cop is a medical person who finds out scientific or material pattern in the evidence collected by them or on-field cops. In some, place forensic cops visit the crime place to collect evidence by themselves.

They do autopsy and do whatever the process needed to know what has actually happened to that evidence collected.  They give date time report along with reason and explanation of the consequences.

using those details, on-field cops/CBI do deeper investigation to reach out to real culprit.

Hope it helps!