You must approach the higher authorities in police department and also FSL Department. Without FSL Report the police cannot file charge sheet as it will be incomplete charge sheet. Further you may approach High Court under Section 482 of Cr.P.C to issue directions to the concerned Investigation Officer and FSL Department to expedite the issue and file charge sheet with in a time bound period.
I could have explained more if background is known to me. I am at your service if you visit my office.
CLICK ‘like’ if satisfied or CLICK ‘Talk to Lawyer’ for further clarifications