IAN WILLIAMS, ITV News Correspondent: Looking for clues. Forensic experts swabbing the charred and twisted metal of one of the railway carriages, trying to find out what explosive was used.
It's a painstaking task picking through the mangled and bloodstained wreckage. Not only was this a methodical, coordinated attack, hitting seven trains in a little over 10 minutes, but each bomb was placed in a first-class carriage, suggesting they were targeting the professionals of India's financial capital.
Here they told me they'd found the remains of a bag in which the bomb was carried, and it was a large device.
INDIAN INSPECTOR (through translator): It must have been three or four kilograms, and you can't fit that into a small box. It could well have been as big as four or five kilos to throw so many bodies out of the train.
IAN WILLIAMS: The damaged trains have all now been moved to a rail yard in the north of the city.
Well, forensic officers are now slowly beginning to piece together what exactly happened. Now, in the case of this particular carriage, they reckon the bomb was at least four to five kilograms and it was kept in the luggage rack up here, blowing the carriage completely apart.
Mumbai's hospitals are struggling to cope with the hundreds of injured, but also with those trying to find missing family or friends. This distraught mother, traveling from hospital to hospital in search of her son. Volunteers, many of them students, are lending a hand.
TANYA GHAVRI, Student Volunteer: They are listed like 50 people, 40 to 50 people who are, like, missing. And we've taken that information now, because their relatives have been coming in and telling us their description. And they have gone to various places looking for them.
IAN WILLIAMS: There's been a massive response to urgent pleas for blood donations. Many of those who survived the blast have horrendous injuries.
In Mumbai's Holy Family Hospital, we spoke to one of the lucky ones: Yogesh Adhia, a lawyer, surrounded by his relieved family, thankful for his remarkable escape from that mangled carriage we'd filmed earlier.
YOGESH ADHIA, Survivor: I saw the people screaming and bleeding all over. And I was also bleeding from my head, because there was some scar. And then I immediately jumped off the train. And after some time, the persons who were in the next compartment, they helped me to the main road. And there I called my friend to pick me up and take me to the hospital.