A preliminary report into last month’s tragic Air India crash has revealed that fuel supply to the aircraft’s engines was unexpectedly shut off moments before the jet went down, killing all 260 people onboard.

The Aircraft Accident Investigation Bureau of India, which released its initial findings early Saturday, disclosed that the engine fuel control switches on the Boeing 787-8 were moved from the active “run” setting to “cutoff” just seconds before the June 12 crash. The aircraft had departed from Ahmedabad and crashed into a nearby residential area shortly after takeoff.

While the report did not assign responsibility or conclude what caused the incident, it noted a tense exchange between the cockpit crew. One pilot reportedly questioned the other on why the fuel had been cut off, only to be met with denial—suggesting potential confusion or technical malfunction in the cockpit.

Images from the crash scene showed the tail section of the plane lodged amid rubble in a densely populated neighborhood. The flight, operating as Air India 171, had been headed to Delhi before the disaster struck.

Investigators continue to examine voice recordings, cockpit systems, and aircraft data to determine what led to the fuel cutoff and whether it was due to human error or a systems failure.

The final report, which could take several more months, is expected to shed more light on what truly led to one of India’s deadliest aviation disasters in recent years.