New Delhi, India - Seventy years ago, India's independence hero Subhas Chandra Bose reportedly died in a mysterious plane crash near Taipei, Taiwan.

But today many Indians believe the crash never happened. Stoking the conspiracy theories, the Indian government remains unwilling to declassify top-secret files on Bose's last days in 1945.

Often known as "Netaji", or "the leader", films and books about Bose's life abound, many focusing on his important role in the liberation of India from British rule.

"Clearly there was something about the way he had lived that continues to tap powerful emotions in India," historian Leonard Gordon told Al Jazeera. "Bose is becoming an unassailable hero and perhaps will in time become a diety."

From the beginning, there was suspicion about the plane crash. Bose's comrade, Colonel Habibur Rahman, who was allegedly with him on the ill-fated airplane, emerged with minor injuries, and refused to tell investigators more.

Several British intelligence officers suspected Bose faked the crash as part of a plan to deceive them and travel to the Soviet Union to seek Joseph Stalin's help in the independence struggle.

In 1998, an Indian government-sponsored enquiry commission found there was no civil aviation record of the crash in Taipei.

During India's 2014 parliamentary elections, the victorious Bharatiya Janata Party (BJP) promised to unravel the mystery of Bose's disappearance.

After BJP leader Narendra Modi became prime minister, he visited a former close associate of Bose, a 99-year-old Japanese Indologist named Sachiro Misumi, and bestowed him with India's third-highest civilian award this year.

But now, Modi's office has said in response to a right-to-information query that it has "no power" to declassify secret files regarding Bose's mysterious demise.

"There are no mentions in Manual of Office Procedure or Public Records Rules, 1997, regarding any discretionary power vested in PM to de-classify records," the Prime Minister's Office (PMO) said last month in a response to a right-to-information application by Sreejith Panickar, an IT professional based in the southern city of Thiruvananthapuram.

Mystery deepens

Last year, when New Delhi-based freedom of information activist Subhash Agarwal appealed to the Prime Minister's Office to disclose records relating to Bose's disappearance, it flatly refused, saying the "disclosure would prejudicially affect relations with foreign countries".

That statement deepened the mystery, raising questions about the possible countries with which relations might suffer if the Bose files were to be made public.

"Modi and the BJP appear on the same page with the Congress [Party]," said Debabrata Biswas, general secretary of the All India Forward Bloc, a party Bose founded after he broke away from the Congress Party in 1939.

"They talked Bose to get votes because they know he is still so popular across India, but they will not do anything to resolve the mystery of Bose's disappearance," Biswas said.

Bose's family has sought the help of Rastriya Swayamsevak Sangh (RSS), the powerful Hindu organisation that has considerable influence over the BJP, for declassification of the secret files in the Prime Minister's Office.

One of the independence hero's nephews, Chandra Bose, has met Modi with a similar request, but to no avail so far.

'Master deception'

Bose, who was in and out of British jails as a Congress Party leader, escaped from his Calcutta home in 1941 and reached Nazi Germany and later Japan, recruiting soldiers for the Indian National Army (INA) from Indian prisoners of war held by the Axis powers.

Bose had foreseen that Russia and the Western powers would [fall out with one another] after the Axis powers were defeated. All evidence points to his desperate attempts to reach Russia. Jayanta Ray, historian

INA fought alongside the Japanese during the 1944-45 campaign in northeastern India and Burma (now Myanmar), but lost out with the Japanese defeat to the Allies. Bose, known for his strong leftist leanings when with Congress, is said to have tried to secure Stalin's support for India's freedom struggle after he realised Japan's defeat was imminent.

"Bose had foreseen that Russia and the Western powers would [fall out with one another] after the Axis powers were defeated. All evidence points to his desperate attempts to reach Russia," said Jayanta Ray, a noted historian and former Centenary Professor at Calcutta University.

Japanese records indicate Bose was on his way to Manchuria in a Japanese bomber when it crashed near Taipei, Taiwan on August 18, 1945.

But many at the time, including senior Congress leaders, saw this as a "master deception" by Bose himself to cover his tracks from the prying eyes of British intelligence. The Congress Party did not even mention Bose's death in obituary references at its annual conference in 1945, which was held after August 18.

After India's independence, two high-profile commissions of enquiry were instituted - one in 1956 and another in 1970 - by successive Congress governments. Both commissions concluded that Bose had indeed died in the plane crash, and his ashes were kept in Japan's Renkoji temple.

But a furious public outcry prevented the Congress government from bringing the ashes from the Renkoji temple, and from giving Bose a posthumous award.

Under much public pressure and on orders of the Calcutta High Court, in 1998 a BJP-led coalition government announced another commission of enquiry, led by former Supreme Court judge Manoj Kumar Mukherjee.

After seven years of painstaking investigation covering Asia and Europe, the Mukherjee commission rejected the plane crash theory as "untenable" in view of insufficient and often contradictory evidence.

"The Mukherjee commission report should be accepted, and a more detailed inquiry should be ordered. The secret files in the PMO are crucial to a successful enquiry on what happened to Bose, and they must be declassified," said Ved Prakash Saini, who heads the Netaji Subhas Kranti Manch, a forum whose goal is to popularise Bose's secular nationalist ideals.

Right to know

But whenever formal requests to declassify the Bose files have been made, they have been summarily rejected.

The future of India

"It is observed that the disclosure of the records [Bose files] was withheld under Section 8(1)(a) of RTI Act on the grounds that it would prejudicially affect relations with foreign countries," appellate official Krishan Kumar said in his 2014 ruling.

Citing a favourable order from the Central Information Commission (CIC) allowing it to withhold information related to the Bose case, the PMO said its decision to withhold the information "is in order insofar as it is consistent with the extant CIC rulings in the matter".

The PMO, however, conceded it possessed 41 files marked "top secret" relating to Subhas Chandra Bose.

In West Bengal, a group of six leftist parties that ruled the state for more than three decades have formally demanded the declassification of the Bose files.

"He was a great national leader, and every Indian has a right to know what happened to him," said Biman Bose, chairman of the Bengal Left Front committee.

Now that the BJP government, like the Congress governments before it, have ruled out declassification of the Bose files held by the PMO, regional parties such as Bengal's ruling Trinamul Congress may make it a big issue in Bengal state elections scheduled for 2016.

But in view of Bose's cult-hero status, there are demands for unravelling the mystery of his end all over India.

"As Indians we have a right to know what happened to Bose," said V Gopalaswamy, popularly known as Vaiko, the leader of the MDMK party in the southern state of Tamil Nadu.

However, by refusing to make the secret files public, the Indian government is only adding to the mystery.