execution petition

I think you have already engaged an advocate and so ask your own counsel.

yes you consult your lawyer and get clarity on it

It is Court that found out the forgery. The court can surely order a Police investigation to find the culprit and file a charge sheet against the person/s responsible for such forgery. 

You have not posted the material facts. The scenario projected, in the normal course of affairs, is rather impossible. 

Taking consideration of the offence of fraud held under Sec 420 and also under some some other sections (if the culprits/ accused persons are not one but more and if some other offences also been held), the Hon'ble court can instruct the police to conduct investigation on it and submit a charge-sheet on it against accused person/s. 

Yes, It will specifically attract Sec 467 IPC Which purports that who so ever forges a document which purports to be a valuable security or a Will...... offence under this is Non Bailable, Non Compoundable and Non Cogzinable one. 

I respectfully disagree with experts as the Executing Court has no such power to consider forgery allegedly committed by decree holder.

However, you did not post relevant facts to form proper opinion and oblige.

It is better to consult your lawyer, if you are affected party.

Prima facie it is an academic topic for debate.

An executing Court cannot go behind the decree or question the jurisdiction of the Court which passed it 

According to section 463 of Indian Penal Code 1860- whoever makes any false documents or false electronic record or a part of the document with the criminal intention to cause, or knowing that he is likely to cause damage or injury to the general public or to any individual, or to support any claim or title, or cause any person to part with property, or enter into implied or express contract or with intent to commit fraud, commits forgery.

The making of a false document in the name of a fictitious person, and making other people believe that it was made by a real person, may also amount to forgery. 

Section 468 is applied and prescribes punishment only to the cases of forgery with the purpose of cheating.

However the burden to prove this act of  forgery will  fall on the person who claims forgery.

Even in that case the executing court may only reject the EP  and cannot go beyond that.

What prevents you from posting material facts. Bits and pieces of disjointed facts and assumptions are of no use.