Seizure memo/ report

Seizure memo can be obtained along with charge sheet. No information or document like seizure memo etc. cannot be shared with a stranger. All investigations begin only on registration of FIR.

Yes, in my opinion too, even if you filed the F.I.R. on behalf of the person whose goods were stolen, as is legally valid, it will not be easy for you obtain the investigation report on a case in which your involvement is not direct. (Unless, perhaps the application is made expressly with the consent of the actual victim.)

I, as a lawyer, filed a complaint on behalf of the aggreived, that X has been committing piracy of my documents. Police conducts investigation after the FIR and prepare a seizure memo. How can I obtain the copy of the seizure memo BEFORE the chargesheet has been filed? and when can I, on behalf of the complainant, request for a copy of the seizure memo AFTER the chargesheet has been filed.

Also, in practical situations, at times, after the FIR has been filed, investigation startes, the police, after being bribed, tend to return the materials back to the accused owner. In that case, can I in any form request the invetigating officer to provide any documentary evidence of confirmation of the fact that such investigation took place?

You have to file application in metroloptan magistrate court (In some states it Judicial magistrate or division magistrate) for release of seized articles on "superdari". Your are not required to bribe the police as police does not have power to release the seized material.  Being the complainant you can obtain the copy of charge sheet, seizure memo etc. from naib court, public prosecutor. By way of RTI you can obtain information of inve4stigation otherwise FIR, chargesheet are sufficient to prove that investigation was carried by police.