You may file for theft and other section as well

No case of forgery is made out 

2) hand writing expert opinion is inconclusive 

3) police would await option of forensic lab to file FIR of forgery 

Judgments depend upon facts of each case 

in your case there is no evidence of forgery 

1.  Bank Draft forgery can be verified from the Original Bank who issued the Draft. "suspected forgery" is not an offence and the officer can only form an legally non-prosecutable opinion. The final expert on this would be a written report of the Forensic Lab.

2. Forgery would mean that the Draft Paper is false, the Hand writing (words, figures, party name, signatures are forged) and all this things can be verified only from the Draft Issuing Bank.

3.  IF forgery /fraud is established, ONLY then the draft depositor (a/c holder) can be liable for criminal prosecution, that too only by the issuing bank.

if the Bank Draft was lost and any complaint in this regard was filed by the owner of the draft before bank and police and the person who present the draft before the bank is not the person in whose name the draft was issued than he commits an offence of attempt to commit misappropriation with 420 of IPC has been made out.

The forensic expert can check for the validity of the draft.and in case it is forged.the issuing bank has to verify same.

See if there is no strict proof they cannot conclude is forgery and on just suspision of forgery no case is made out.

That a close scrutiny of the provisions makes it clear that, Section 463 defines the offence of forgery, while Section 464 of IPC substantiates the same by providing an answer as to when a false document could be said to have been made for the purpose of committing an offence of forgery under Section 463. That Section 464 of IPC defines one of the ingredients of forgery i.e. making of a false document. Further, Section 465 of Indian Penal Code provides punishment for the commission of the offence of forgery.

Now first you have scrutinize that whether really a documents is forgery or suspected means have suspect's doubt in the document whether it's forgery or not. So one needs to prove first this and check from all aspects.

I can provide you supreme court decision.

You can file for forgery in court and if you have evidence can prove the same

Dear Client,

Forgery includes false document, signature, or other imitation of an object of value used with the intent to deceive another.

Person who commit forgery are often charged with the crime of fraud.The most common form of forgery is signing someone else's name to a cheque.

Sec 511 IPC.

Simply falsifying a letter or document does not constitute forgery unless the person does so in attempt to defraud a person or entity. 

Forgery is transfer of property by misrepresentation.

And suspected forgery is that they have denied the transaction due to suspected forgery and it doesnt attract charges of forgery because there no transfer of money took place. 

A complaint can be lodged with the concerned police station about this.

Suspicion about the forgery itself is a strong ground for lodging a criminal complaint.

You may proceed with the complaint.