(Reuters) -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 Boeing 787 jet's engines, the Wall Street Journal reported on Wednesday.

Following is a timeline of key events in the investigation to date:

JUNE 12:

An Air India Boeing 787 Dreamliner bound for London crashes shortly after takeoff from Ahmedabad city, killing all but one of the 242 people on board.

JUNE 13:

India's Aircraft Accident Investigation Bureau (AAIB) launches an investigation into the world's deadliest crash in a decade.

Its multidisciplinary team is led by the director general of the AAIB, and includes an aviation medicine specialist, an air traffic control officer, and representatives from the U.S. National Transportation Safety Board (NTSB).

Two GE recorders, one in the jet's front and another at the rear, are installed on Boeing's ( BA ) 787 jets. Both contain a cockpit voice recorder and a flight data recorder with the same sets of data.

One black box unit is recovered from the rooftop of a building at the crash site.

JUNE 16:

The second black box unit is recovered from debris at the crash site.

JUNE 24:

The two black box units were flown separately from Ahmedabad to an AAIB lab in Delhi by Indian Air Force aircraft.

In the evening, the team led by the AAIB director general with technical members from AAIB and the NTSB began the data extraction process.

JUNE 25:

The memory module from the black box unit located at the front of the plane was successfully accessed and its data downloaded.

The forward recorder is equipped with an independent power supply that provides backup power to the device for about 10 minutes if the plane's power source is lost, the NTSB said in a 2014 report.

JULY 12:

A preliminary report by Indian investigators said there were no recommended actions to Boeing ( BA ) or GE at this stage, indicating a fault in the aircraft or engines was unlikely.

It said one pilot can be 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.

It did not identify which remarks were made by the flight's captain and which by the first officer, nor which pilot transmitted "Mayday, Mayday, Mayday" just before the crash. 

A final report is expected within a year of the crash.

JULY 16

The Wall Street Journal reports the first officer, who was flying the plane, asked the more experienced captain why he moved the fuel switches to the "cutoff" position seconds after lifting off the runway.