Registration of FIR is not mandatory for starting investigation in a cognizable offence. If there is commission of a cognizable offence about which complaint has been made, there is no legal bar on calling the accused to police station even before registration of a formal FIR. However, calling the accused for negotiating with the complainant may not be permissible since it is not the job of police to facilitate negotiations between parties.
Depending upon what injuries have been caused during the assault, the relevant sections of IPC (such as Section 323, 324, etc.) may be applicable against the assailants. If the police officer has not been involved in the assault directly or indirectly, then he may not be directly an accused in the assault case. But, he may be responsible for his negligence in performing his duties and failing to prevent / control the assault. Depending on facts of the case, such police officer may be liable for the assault sections, or under Section 166 IPC or 221 IPC or may be only for departmental action. It will depend on the detailed facts of the case.
Dr. Ashok Dhamija is a New Delhi based Supreme Court Advocate and author of law books. Read more about him by clicking here. List of his Forum Replies. List of his other articles. List of his Quora Answers. List of his YouTube Videos.