Crash investigators from the United States have reached Ahmedabad to help piece together how one of India’s worst plane disasters unfolded, with Indian government officials saying the cockpit voice recorder had been recovered.

The investigators, from the U.S. National Transportation Safety Board, are conducting “a parallel probe under international protocols since the aircraft is American-made,” the Indian government said in a statement late Sunday.

Government officials also said that both the flight data recorder and cockpit voice recorder had now been located. The flame-resistant “black box” devices could hold information about what happened leading up to the disaster, including the final communications between the pilots of the plane, which crashed less than a minute after takeoff.

At least 270 people, including 241 passengers on an Air India flight bound for London Gatwick Airport from the city of Ahmedabad, in the western Indian state of Gujarat, died last week as a Boeing 787-8 Dreamliner plane smashed into buildings including the dining hall of a medical college.

The intensity of the flames from the crash has made the identification of passengers a mammoth task. As of Monday afternoon, 99 victims had been identified by matching their DNA with samples from relatives, said Dr. Rakesh Joshi, superintendent at the Ahmedabad Civil Hospital, where most of the bodies are being held. So far, the remains of 64 victims have been handed over to family members.

“Slowly and steadily the process is becoming faster,” Dr. Joshi said. “We’ll finish in a day or two.”