Original advocate or p.p

It has been ruled by the Supreme Court that in a criminal matter covered under the IPC (unlike DV cases which are quasi-criminal), the PP and only the PP can represent the state/govt. This is required to assure that the defendant gets a fair trial. The complainant's advocate can assist the PP but not take the lead or examine witnesses. There are a few supreme court cases on this. For example, read this: https://indiankanoon.org/doc/385118/