Signatures forged

What is the document on the basis of that case has been filed? How do you say that it your mother's forged signature?

Sir,

Assuming that someone has filed a criminal complainant against your mother creating forged documents.

In this case you have to raised objection before the concerned court by filling an application under Section 91 Cr.P.C and requesting the concern court to sent the documents for FSL immediately.

file an application under section 91 Cr.P.C, requesting concerned court to send the documents for FSL and if the matter is pending before Police investigation then file an application before Investigating officer requesting him for sending the documents for FSL.

Toundri,

You may file a petition u/s 45 of Indian Evidence Act to obtain an opinion by the handwriting experts in this regards,which will prove genuineness of the signatures on comparison.

You are questioning a document alleging that it is forged.  It comes in the domain of experts that deal with questioned documents.  FSLs do that job. They could determine , even from the paper, when it was manufactured , and from the analysis of spread of the ink, composition of ink, folds on the paper, and several other factors and it is highly specialised job.  You may need to go through the procedures suggested to have the document examined to sustain or reject the claim