1.it is sad that even on the wake of such extreme tortures no FIR is registered as yet.
2.ANyway meet the SP or the commissioner with a written complaint. I am sure the FIR would be registered.
3. if not then file an application u/s 156(3) crpc in the magistrate's court and then court would direct the registration of FIR.
4. You can also file writ petition against police inaction if the influence on police remain intact.