It is the photograph that has dominated the world's front pages, casting an astonishing light on the fresh-faced killers who brought terror to the heart of India's most vibrant city. Now The Independent can reveal how the astonishing picture came to be taken by a newspaper photographer who hid inside a train carriage as gunfire erupted all around him.

Sebastian D'Souza, a picture editor at the Mumbai Mirror, whose offices are just opposite the city's Chhatrapati Shivaji station, heard the gunfire erupt and ran towards the terminus. "I ran into the first carriage of one of the trains on the platform to try and get a shot but couldn't get a good angle, so I moved to the second carriage and waited for the gunmen to walk by," he said. "They were shooting from waist height and fired at anything that moved. I briefly had time to take a couple of frames using a telephoto lens. I think they saw me taking photographs but theydidn't seem to care."

The gunmen were terrifyingly professional, making sure at least one of them was able to fire their rifle while the other reloaded. By the time he managed to capture the killer on camera, Mr D'Souza had already seen two gunmen calmly stroll across the station concourse shooting both civilians and policemen, many of whom, he said, were armed but did not fire back. "I first saw the gunmen outside the station," Mr D'Souza said. "With their rucksacks and Western clothes they looked like backpackers, not terrorists, but they were very heavily armed and clearly knew how to use their rifles.

"Towards the station entrance, there are a number of bookshops and one of the bookstore owners was trying to close his shop," he recalled. "The gunmen opened fire and the shopkeeper fell down."

But what angered Mr D'Souza almost as much were the masses of armed police hiding in the area who simply refused to shoot back. "There were armed policemen hiding all around the station but none of them did anything," he said. "At one point, I ran up to them and told them to use their weapons. I said, 'Shoot them, they're sitting ducks!' but they just didn't shoot back."

As the gunmen fired at policemen taking cover across the street, Mr D'Souza realised a train was pulling into the station unaware of the horror within. "I couldn't believe it. We rushed to the platform and told everyone to head towards the back of the station. Those who were older and couldn't run, we told them to stay put."

The militants returned inside the station and headed towards a rear exit towards Chowpatty Beach. Mr D'Souza added: "I told some policemen the gunmen had moved towards the rear of the station but they refused to follow them. What is the point if having policemen with guns if they refuse to use them? I only wish I had a gun rather than a camera."