Eyewitnesses have been describing their shock after a shooting incident at a leading research institution in the southern city of Bangalore on Wednesday.
The attack spread alarm across the campus
A college professor was killed and at least four others injured when a gunman entered the Indian Institute of Science and opened fire at scientists and laboratory technicians attending a conference.
One eyewitness, Prof S Sadagopan, director of the Bangalore-based Indian Institute of Information Technology, told the BBC people had run in panic.
"There were about 70 to 100 people, many of whom came running inside the auditorium.
"Some talked of seeing a grenade-kind of material lying on the ground. It looked like a terrorist attack. We are shell shocked."
Prof Sadagopan told the Indian Express newspaper the firing had been "intense" and came after the main programme of the day was over.
"A few of us were walking to the next building when we heard sounds like the heavy use of firecrackers.
"Someone was throwing crude bombs and shooting randomly in the walkway between the buildings.''
Another conference delegate, Dr G Sreekanteswara, also thought the bangs he could hear were fireworks.
"We first thought it was crackers bursting. The bullets were fired on the building and not knowing what was happening, we ran for safety," he told the BBC.
A security guard posted in the campus said he saw a man with a gun.
"We heard a sound and came out to look. Just then a man came running with a gun firing," said the guard, who preferred to remain unnamed.
'Caught by surprise'
PK Kapur, a management studies teacher, said he had seen a man with a gun firing away.
"I realised that it was a gun firing when a bullet zipped past. I saw a man with a gun at a distance of 100 metres open fire at us," he told the Deccan Herald newspaper.
"After a few minutes, he ran out of the campus while he continued to fire," he said.
Dr Chandra K Jaggi, another eyewitness, said: "I and others were caught by surprise. I could hear some persons cry in pain. Then I thought it was an attack and informed the police."
Reports said 250 Indian and 56 foreign delegates were attending the conference when the attack happened.