Police searching the home of Germanwings crash co-pilot Andreas Lubitz may have discovered a "significant clue" about the tragedy.

Officers have been combing the property in Düsseldorf, Germany, for clues about why Lubitz, 28, apparently deliberately crashed the flight into the French Alps.

A total of 150 people were killed in the crash earlier this week - some of them youngsters. Markus Niesczery of Düsseldorf Police said: "We wanted to search to see if we could find something that would explain what happened.

"We have found something which will now be taken for tests. We cannot say what it is at the moment but it may be a very significant clue to what has happened.

"We hope it may give some explanations," he told the Daily Mail.

Germanwings airline issued a statement revealing it believes the flight was crashed on purpose by co-pilot Lubitz, who locked himself in the cockpit.

The focus in the aftermath of the crash has been upon his background, with reports he received treatment for a "severe depressive episode" in 2009. German tabloid Bild made the claim in a report, adding he was pronounced "not suitable for flying" by a flight school in Arizona, in the US.