A cockpit recording of dialogue between the two pilots of the Air India flight that crashed last month indicates the captain cut the flow of fuel to the plane’s engines, the Wall Street Journal reported on Wednesday.

The newspaper cited people familiar with US officials’ early assessment of evidence uncovered in the investigation into the June 12 crash in Ahmedabad, India, that killed 260 people.

The first officer, who was flying the Boeing 787 Dreamliner, asked the more experienced captain why he moved the fuel switches to the “cutoff” position seconds after lifting off the runway, the report said.

The two pilots involved were Captain Sumeet Sabharwal and First Officer Clive Kunder, who had total flying experience of 15,638 hours and 3,403 hours, respectively.

India’s AAIB, Directorate General of Civil Aviation, Ministry of Civil Aviation, Boeing and Air India did not immediately respond to Reuters’ requests for comment on the Wall Street Journal report.

A preliminary report into the crash released by India’s Aircraft Accident Investigation Bureau (AAIB) on Saturday said the fuel switches had switched from run to cutoff a second apart just after takeoff, but it did not say how they were flipped.

One pilot was then heard on the cockpit voice recorder asking the other why he cut off the fuel. “The other pilot responded that he did not do so,” the report said.

Without fuel flowing to the engines, the London-bound plane began to lose thrust and sink. Almost immediately after the plane lifted off the ground, closed-circuit TV footage showed a backup energy source called a ram air turbine had deployed, indicating a loss of power from the engines.

At the crash site, both fuel switches were found in the run position and there had been indications of both engines relighting before the low-altitude crash, the report said.

In an internal memo on Monday, Air India CEO Campbell Wilson said the preliminary report found no mechanical or maintenance faults and that all required maintenance had been carried out.

The AAIB’s preliminary report had no safety recommendations for Boeing or engine manufacturer GE.

After the report was released, the US Federal Aviation Administration and Boeing privately issued notifications that the fuel switch locks on Boeing planes are safe, a document seen by Reuters showed and four sources with knowledge of the matter said.