Can file FIR for recovery of documents. On his intestate death, you and mother inherited his every single assets equally.

File suit of recovery of possession.

See if there is will then mother can file for probate of such will and can give notice to uncle through court to bring the property documents on record.

Further if there is no will she and you can file for possession of property and give notice for documents.

See a FIR in police may be given by giving a written complaint though police may deny same citing it civil matter.

Issue legal notice to uncle to furnish copy of father death certificate and file documents of property standing in deceased father name 

2) you can also take search at sub registrar office and obtain certified copy of tile deeds 

3) your mother should apply for probate of father will

4) probate is judicial proof that will is genuine 

Contact a local lawyer for issue of legal notice 

he can draft FIR to e filed by you 

You can send them legal notice to give custody of the said documents otherwise file suit in civil court

1. AS may be required, put the Paternal Uncle on Legal Notice, to inspect and provide all the belongings and documents of Father. Death Certificate can be obtained from the local Municipal of Gram Panchayat office.

2. AFTER above and based on the WILL document of Father, the properties etc.... can be divided amongst the legal heir as per the clauses of the WILL.

3. IF both above, is not possible, THEN the last remedy is to file a Civil Suit in the local Civil Court, by making the Paternal Uncle as party and seek appropriate directions for all the belongings and documents & properties of Father. 

- Since , your deceased father has left already WILL in the name of your mother , hence now she become the legal owner of the property. 

- You mother should apply for getting the details of the property in the office of Registrar of your area. 

- Further,if your paternal uncle is not ready to give all other documents  , then you should issue a legal notice to him , for the same.

- If, no response, then your mother should file a case in the court for getting probate order on the ground of WILL 

- In probate case , court will issue summon to your uncle to handing over those documents or for filing objection if any by him. 

1. You can lodge complaint with police against uncle that he have seized documents and other details of father's property and bank accounts.

2. Send legal notice to uncle for handover the documents and belongings of father as his legal heirs.

As he was your father, you and your mother and your siblings have a share in his property. Also if he has made a will then the property shall be distributed as per the contents of the will.

Obtain a copy of the will from the registrar office.

In case he refuses file a declaratory suit making all shareholders party to the suit.

Your mother is entitled to a share in all his properties including his terminal benefits, if he was employed before his death.

Besides your mother you are also, as one of the legal heirs, entitled to an equal share in your father's properties left behind upon his intestate death.

You can apply for death certificate from the concerned authority.

You can obtain the property documents from his paternal uncle or you can get a certified copy from the registrar's office too.

Take the assistance of an advocate in the local in case it is necessary.

It may not be necessary to file any FIR especially before exhausting the remedy of asking that person to hand over the documents.

If he is denying possession of any document then there wont be any use of this FIR also.

Just mention in FIR that uncle has forcibly took custody of property documents belongs to you and mother by inheritance and uncle wants to sell the property illegally and is in illegal possession of father property. - Criminal trespasser.

As the property being self acquired of your father, your uncle has no right as you and your mother are the heirs and legal representative of your father and his property. contact local lawyer in this regard. 

issue a legal notice to your uncle and ask to handover death certificate and will copy and other documents. as legal heir you and your mother having rights to claim legally. 

1. You can obtain a certified copy of his death certificate if his death has been registered with the municipal corporation. Certified copies of sale deeds of properties owned by him can also be obtained from the office of jurisdictional sub-registrar.

2. His property has devolved in terms of the will made by him.