RAJSHAHI, Bangladesh – Days after his colleague was butchered by Islamist extremists at their university in Bangladesh, Mahbub Alam answered a call from a mystery number that made his blood run cold.
"The person on the other side of the line said to me: 'Your life has come to an end. You've gone too far. Wait and see what happens to you.'," said Alam, a professor of public administration at Rajshahi University.
"I've never been connected to any type of activity except teaching. I've no idea what I've done to receive such a threat.
"It's OK when someone confronts you face-to-face. But if someone attacks you from behind, what can you do except live in fear?"
Normally a hive of activity, the university campus has been largely deserted since English professor Rezaul Karim Siddique was hacked to death late last month while walking from his home to a bus stop.
His attackers ambushed the 58-year-old from behind before flaying him with machetes in broad daylight, nearly severing his neck in the process.
It was the latest in a string of gruesome murders carried out by Islamist extremists in the last 3 years, with other victims including secular bloggers and members of the mainly Muslim country's religious minorities.
Extremist target
But professors teaching at Rajshahi in northwestern Bangladesh, which has a reputation as one of the country's most liberal universities, have been a target of extremists for more than a decade.
Four have been killed since 2004 while more than 50 teachers say they have received threats from Islamist extremists.
After Siddique's murder, teachers went on an unofficial strike which prompted most of the university's 33,000 students to head home and begin their summer holidays early.
When an Agence France-Presse correspondent visited the 752-acre (300-hectare) campus last week, the lecture halls were empty and the only significant gathering was at a rally attended by teachers and students to protest Siddique's slaughter.
Much of the anger was directed at the government of Prime Minister Sheikh Hasina which has been accused of showing little sympathy towards the victims and doing little to improve security.
Nearly all recent attacks have been claimed by Al-Qaeda's local branch or the Islamic State (ISIS) organization but the government insists neither group has got a foothold in Bangladesh, blaming its domestic opponents instead.
"We are feeling very isolated and are all in a bit of a panic," sociology professor Nilufar Sultana told Agence France-Presse.
"The authorities are not assuring any security. They aren't even saying that they're looking for the killers. It's deeply frustrating."
Mamunul Habib, who was taught by Siddique, said that no one could concentrate on their studies for the moment.
"We can't pick up weapons to protect ourselves and of course it's not for us to do that anyway," said Habib.
"It's impossible mentally to study and work in such a climate, especially as you can't help feeling that you could be the next target."
After Siddique's killing, it emerged that a hit-list with the names of 10 people – including the university's vice-chancellor – had been distributed on a leaflet in the nearby town of Natore.
'We feel helpless'
The leaflet bore the name of an obscure group called the Islami Liberation Front which said its objective was to establish an Islamic caliphate by toppling what it called the "repressive" government.
No one has so far been charged with Siddique's murder although police have made four arrests and say one of those has confessed to taking part in the killing.
Rajshahi police commissioner Mohammad Shamsuddin acknowledged people felt nervous but said his officers were doing all they could to avoid a repeat.
"This sense of panic will gradually fade and we are working very hard to provide security to everyone in the city," Shamsuddin told Agence France-Presse.
However the murder on May 6 of a local leader of the Sufi Muslim minority around 40 km (25 miles) away has heightened fears that the killers may still be at large, with the victim also hacked to death.
"We now feel very helpless," said Professor Moloy Voumik, another of Siddique's former colleagues who admits he is living in fear.
"I know if these targeted killings continue, then my name will definitely find a place on their hit-list." – Rappler.com