There are three possible paths in the Netaji mystery. Path 1 is where the aircrash story was true and he died in 1945. This has been the official narrative but frankly speaking there is no evidence except for the many contradictory statements from Habibur Rahman and the so called Japanese survivors and witnesses of the crash. Justice Mukherjee, Netaji’s elder brother Suresh Chandra Bose and Prof. Samar Guha have already demolished this myth. The details of Samar Guha's arguments are provided in the metamorphosis chapter of the digital history link HOME | netajisubhasbose
None of the Bose family members close to Netaji like Sarat Bose, Suresh Bose, Aurobindo Bose, Dwijen Bose (his nephews) believed in the plane crash theory. Needless to say that they had pretty good reasons not to.
The second path is his possible death in Russia. This also has no evidence except for some hearsay on how he was tortured in a Russian prison or spent time in Gulag. There is no documentary evidence of death. It is a very big assumption without basis and can be set aside. Dr. Purabi Roy, Maj.Gen G. D Bakshi are the chief proponents.
The third path is that he returned to India but often traveled to his Horizon to the West of Pamirs and he was known Bhagwanji or Mahakal. Many ardent followers of Netaji like Dr. Pabitra Mohan Roy, Leela Roy, Sunil Das, Anil Das, Sunil Krishna Gupta were active proponents of this theory because they had been intimately associated with Bhagwanji as well. As per documented evidence, Bhagwanji was involved in geopolitical activities of far reaching consequences as narrated by he himself. Though it sounds fantastic this theory emerges as the strongest because of the volume of documentary and forensic evidences. There are a large number of documents with the followers of Bhagwanji that prove Netaji-Bhagwanji linkage. His handwriting was matched by atleast three top experts like B. Lal Kapur, Curt Baggett and more recently by Ashok Kashyap (the later two were consulted by Mission Netaji). He was identified by long time Netaji associates like Leela Roy, Dr. Pabitramohan Roy, Anil Das, Sunil Krishna Gupta and several others who had seen Netaji had also seen him like Shrikant Sharma, Surendra Choudhury and Durgaprasad Pandey. The DNA mismatch is a fraud as recently revealed since the agency CSFL could not provide the electropherogram report, the back bone of DNA analysis. Their report was debunked recently by another well known DNA expert Gyaneswar Chaubey as an absurd report on technical grounds. The DNA test in Hyderabad was inconclusive. Even though in absence of the DNA test matching Justice Mukherjee could not conclude that Mahakal was Netaji, he nevertheless told in an informal interview that he was 100 percent sure that Bhagwanji was Netaji. Researchers like Anuj Dhar and hiss team of Mission Netaji have been pioneers in declaring Bhagwanji as Netaji but there are others who also open support and promote the theory like Dr. Jayanta Choudhury, Dr. Madhusudan Pal, Bijoy Nag of Jayasree patrika, Keshab Bhattacharya, Amlan Kusum Ghosh, among others. So there is absolutely no doubt on path 3. Path 1 is already discredited. Path 2 does not have any evidence but path 3 is the strongest possibility with enough documents and other evidences admissible in a court of law.