A top Bangladeshi author wounded in a knife attack in Dhaka in February has now been found dead in Germany, his relatives have said.
Azad blamed fundamentalists for February's attack
German officials in Dhaka told the family that Humayan Azad, 57, had died in his sleep in his flat in Munich.
However, family and colleagues are calling for a full investigation.
Humayan Azad, a professor at Dhaka University, was seriously wounded in February's knife attack on the campus. He blamed hardline Islamic groups.
He was recently denounced by a number of Islamist parties in Bangladesh for writing a book critical of some Pakistanis for their role before Bangladeshi independence in 1971.
The news of the professor's death sparked a demonstration by students on the Dhaka University campus, echoing similar demonstrations following the knife attack in February.
Professor Azad's son, Ananya, has said he was abducted briefly last month at the university and was asked about his father's whereabouts.
Professor Azad himself had told the BBC he had received several death threats before going to Germany last Saturday at the invitation of a writers' organisation.
A German embassy official told the family the professor had died sometime between Wednesday evening and Thursday morning.
Munich police spokesman, Dieter Groebner, said an autopsy indicated death was due to heart failure. "There is absolutely no evidence of any violence."
He said results of tests for poisons would be available in a few weeks.
The professor's daughter, Mouli Azad, said her father had had a full check-up before his departure.
"So the theory that he died of a heart attack is not believable to us, there must be something behind it," she said.
The president of Dhaka University Teachers Association, Professor Arefin Siddiqui, said: "We want a full report on how he died and in which circumstances. He had received a threat on his life before his departure, so everyone here is sceptical."
Another leading writer and colleague, Professor Anisuzzman, said Professor Azad's death marked a "great loss to Bengali literature".
The knife attack in February left the professor with serious head and neck wounds.
At least 60 people were injured in clashes between police and protesters who demanded the resignation of the home minister.
The professor's attack sparked protests by his students
The professor, author of about 50 books, said he believed the attack on him was carried out by those people "who believe in the ideas of fundamentalism".
He pointed out that two daily newspapers seen as the mouthpieces of hardline Islamic groups had written articles against him, and an MP had severely criticised him following the publication of his latest book.
Entitled Pak Sar Zamin Sad Bad - the first line of the Pakistan national anthem - it strongly criticised the rise of Islamic extremism in Bangladeshi society in recent years.
Several Islamic groups quickly denounced the novel and demanded it should be banned.
Two months ago, a death threat against the professor and two colleagues was faxed to the press, saying: "If they don't redeem themselves by September this year they will be killed."