(This story originally appeared in on Sep 23, 2013)

NEW DELHI: A hoax call from a PSU woman officer who convincingly sounded like Sonia Gandhi , an agitated attorney general of India who received that call and was convinced that a not-too-happy Congress president was on the line, an informal CBI inquiry into the matter, and now a formal Delhi Police inquiry into the complaint filed on the hoax call.

Home minister Sushil Kumar Shinde confirmed such a hoax call had been made and that the matter was referred to the home ministry. He declined to give further details.

ET has confirmed the details of this extraordinary event, which a senior political figure described as "equally serious and farcical", with senior Congress leaders, cabinet ministers, senior government officials and senior officers of CBI and Delhi Police.

No one ET spoke to was willing to go on record, saying the matter was too sensitive and still under inquiry. Attorney general Goolam E Vahanvati and law minister Kapil Sibal also refused to comment on the matter.

Since no FIR has been filed and the police inquiry is at a very early stage, ET has decided not to reveal the names of the hoax caller, or a law officer and a senior Congress leader who the police suspect may be the prime movers behind the hoax call.

ET pieced together the sequence of events after several conversations with senior establishment figures. Vahanvati started receiving calls early this month from a person claiming she was calling from Sonia Gandhi's office. Gandhi was in New York for a medical checkup during that time. She had left for abroad on September 1, according to media reports.

Shortly thereafter, Vahanvati received a call from a woman who, as a senior police officer told ET, sounded "almost exactly like Sonia Gandhi". The caller was a PSU employee, CBI and Delhi Police officials told ET. In Delhi power circles, some officials and politicians said, she's known as someone who can imitate the voice of one of India's most powerful women.

The alleged hoax caller, pretending to be Gandhi, told Vahanvati she was calling from New York - where Gandhi was actually staying at that time - and, as ET has learnt, managed to convincingly sound unhappy over what she said was the AG's handling of several crucial and high profile cases, including those related to coal allocations.

The woman pretending to be Gandhi told the attorney-general he should consider "lying low and taking fewer responsibilities".

The hoax caller strongly suggested, officers inquiring into the case told ET, that she wasn't happy with Vahanvati's performance so far. A senior Congress leader said the hoax caller also suggested the AG should consider resigning.

ET has confirmed with senior Congress leaders that the AG, convinced it was Gandhi who had called him, contacted and/or met important government and political figures to seek clarity on the matter.

"After all, there's no precedence ever of Mrs Gandhi calling a law officer directly... she simply doesn't do such things," a senior Congress leader told ET. It was only after his meeting with senior establishment figures that Vahanvati learnt Gandhi hadn't called him, and that there was no question of her calling him on official matters.

The home ministry was notified and the matter was thereafter referred to CBI. A senior CBI officer, who did not wish to be named, told ET the agency had sent officers to make informal inquiries and was able to establish the call was a hoax. The hoax caller was also identified.

"We referred the matter to the Delhi police since this doesn't fall in CBI's ambit. We also didn't wish to get mixed up with internal law ministry politics," said the CBI officer.

Further inquiries revealed the possibility that another law officer and a senior Congress leader may have persuaded the woman PSU employee to make the call.

The matter is now with the Delhi Police, which is looking into the complaint. Delhi Police officers, speaking on the condition they not be identified, confirmed the chain of events to ET and said an FIR hasn't been filed as yet but an inquiry is on. Officers said they hoped to finish the preliminary inquiry soon.

Senior Congress leaders told ET the incident reveals a worrying aspect of intra-party and intra-government rivalry. The possible involvement of a Congress leader and another law officer "takes the matter far beyond a prank", a very senior party functionary said.