Who did Jaswant Singh have in mind when he wrote about a US mole in the PMO during the tenure of PV Narasimha Rao? No one knows for sure, as there is no conclusive evidence to establish his identity.
The mole mentioned in Singh's book -- A call to Honour -- is in the context of India's nuclear programme and the reference to him has been made on page 126.
If Singh's claim is true, sources say, the needle of suspicion could point towards someone who was assisting Rao on subjects pertaining to nuclear, scientific and defence matters.
And since the PM has more than one person to seek counsel in such matters, it is difficult to pinpoint anyone with conviction.
It is significant to point out that the role of a senior functionary in the PMO was under scrutiny by the intelligence agencies at one stage as several files pertaining to officials/scientists who went abroad but never returned went missing.
Subsequently, a senior functionary was also accused as a "liaison man" behind the controversial Sankhya Vahini project by the RSS during the NDA rule. He had denied the allegations.
The intelligence agencies also had no proof of either him or his associates operating on behalf of the Americans and they continue to be respectable Indians.
Similarly, some functionaries of the AB Vajpayee government were also at one stage accused of being close to the Americans but that did not make them moles. In the past, a former foreign secretary was also under the scanner for being close to the CIA.
There have been instances of several top officials being linked to foreign powers but no charges have ever been proved. Dr PC Alexander (now a Rajya Sabha member), who served as principal secretary to Indira Gandhi and later Rajiv Gandhi, had to leave briefly after his personal staff was allegedly involved in the infamous Coomar Narain case.
There were more such allegations. Maneka Gandhi, when she edited the "Surya" magazine in the late Seventies, had published snaps of four senior Congressmen who were allegedly close to the CIA.
Former PM Morarji Desai was named by journalist Seymour Hersh to be a CIA mole in Indira Gandhi's ministry. The journalist obviously got the name wrong since Desai was not part of the Indira government in the early Seventies.
Henry Kissinger, secretary of state under Richard Nixon, many years later told a senior Indian journalist that there indeed was a mole in the Indira cabinet who had tipped the Americans that after Bangladesh, the Indian PM would attack West Pakistan and reclaim Kashmir.
And that is why the Seventh Fleet was sent. But Kissinger said it was part of a deal with the then CIA director that they would never ask the name of the agency's moles. Since Morarji was ruled out, till this date there has only been speculation about the informer.