The captain of the Germanwings jet that investigators believe was deliberately crashed into the French Alps killing all 150 aboard, shouted at the co-pilot to “open the damn door” as he desperately tried to get back into the locked cockpit, German newspaper Bild has reported.

French officials said the plane’s black box voice recorder indicated that the co-pilot Andreas Lubitz, 27, locked the captain out of the cockpit of the jet and steered Flight 4U 9525 into a mountainside.

The officials believed the more senior pilot, identified by Bild as Patrick S, tried desperately to reopen the door during the flight’s eight-minute descent after he had left to use the toilet.

Bild reported that data from the cockpit recorder showed the captain shouted: “For God’s sake, open the door”, as passengers’ screams could be heard in the background.

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It said “loud metallic blows” against the cockpit door could then be heard, before another warning alarm went off and the pilot was heard to scream to a silent Lubitz in the cockpit “open the damn door”.

Bild reported that earlier in Tuesday’s flight between Barcelona and Dusseldorf, the captain was heard explaining to his colleague that he had not had time to go to the toilet before take off.

As investigators seek to build up a picture of Lubitz and any possible motives, media reports have emerged that he suffered from a problem with his eye, adding to earlier reports he was severely depressed.

Earlier, German prosecutors said they believed Lubitz hid an illness from his airline employer but did not specify the ailment. They added he had been written off sick on the day the plane crashed.

Lubitz treated for eyesight problems: reports

Pilot Andreas Lubitz crashed the Germanwings plane after locking his captain out of the cockpit.

Bild and the New York Times, which cited two officials with knowledge of the investigation, said Lubitz had sought treatment for problems with his sight.

Bild reported that investigators found evidence that Lubitz feared losing his eyesight because of a detached retina.

Bild’s Saturday edition had published an interview with a flight attendant who it said had a relationship last year with Lubitz and recalled him saying: “One day I’m going to do something that will change the whole system, and everyone will know my name and remember”.

The flight attendant told Bild if Lubitz did deliberately crash the plane, it was “because he understood that because of his health problems, his big dream of a job at Lufthansa, a job as a captain and as a long-haul pilot was practically impossible”.

German prosecutors revealed Friday that searches of Lubitz’s homes netted “medical documents that suggest an existing illness and appropriate medical treatment”, including “torn-up and current sick leave notes, among them one covering the day of the crash”.

Police found a number “of medicines for the treatment of psychological illness” during a search at Lubitz’s Dusseldorf home, Welt am Sonntag newspaper said.

It added that the Germanwings co-pilot was suffering from being overstressed and was severely depressive, according to personal notes found.

Search for second black box continues

French police investigator Jean-Pierre Michel said on Saturday that Lubitz’s personality was a “serious lead” in the inquiry but not the only one.

The investigation has so far not turned up a “particular element” in the co-pilot’s life which could explain his alleged action, he said.

Lufthansa, which operates the budget carrier Germanwings, chief Carsten Spohr said earlier that Lubitz had suspended his pilot training, which began in 2008, “for a certain period” before restarting and qualifying for the Airbus A320 in 2013.

The second-in-command had passed all psychological tests required for training, Mr Spohr told reporters.

Germany is to hold a national memorial ceremony on April 17 for the victims of the disaster, half of whom were German, with Spain accounting for at least 50 and the remainder composed of more than a dozen other nationalities.

Meanwhile, helicopters resumed search operations at the crash zone in south-eastern France for a sixth day, as efforts to comb the area for the victims’ remains and a second black box continue.

“There’s no reason not to find the second black box,” French investigator Xavier Vialenc said.