German public prosecutors in Duesseldorf said Monday that the co-pilot of the crashed Germanwings plane had received treatment because of suicide risk several years ago, but there was no proof he had had suicidal tendencies or aggression since then.

Information gathered from an audio recorder of the crashed flight 4U9525 led French prosecutors to believe that the co-pilot, Andreas Lubitz, deliberately crashed the plane last Tuesday.

Media have been reporting that Lubitz may have been dealing with mental health issues.

"There is so far no evidence of any organic diseases of the co-pilot, according to medical documentation obtained," said prosecutors in the western German city in a statement on Monday.

However, several years ago, before Lubitz got his pilot certificate, he had undergone psychotherapy treatment because of suicide risk, confirmed the prosecutors.

The 27-year-old co-pilot had not been attested as having suicidal tendencies or aggression during his doctor visits in the subsequent period, the statement added.

Prosecutors did not give information on Lubitz's possible motives, saying there was a lack of clear information indicating any motives and "they will not and cannot involve in speculations over motivations of the co-pilot."