Prosecutors investigating the Germanwings crash have said there were indications the co-pilot hid his illness from his employers.

In a news conference on Friday, the prosecutors said that Andreas Lubitz (27) hid a sick note on the day the Airbus A320 crashed into a mountainside during a flight from Barcelona to Dusseldorf.

The torn-up note, dated on the day of the crash on Tuesday, was found during searches of the his apartment in Dusseldorf and the home he shared with his parents in the town of Montabaur.

The prosecutors added that documents showed he was receiving medical treatment, but that no suicide note or claim of responsibility for the crash was found.

They said: "Documents with medical contents were confiscated that point towards an existing illness and corresponding treatment by doctors."

"The fact there are sick notes saying he was unable to work, among other things, that were found torn up, which were recent and even from the day of the crime, support the assumption based on the preliminary examination that the deceased hid his illness from his employer and his professional colleagues."

No evidence of a political or religious motivation behind the crash was found.

Senior prosecutor Ralf Herrenbrueck said: "The fact, that torn-up current sick notes were found which also cover the period of the day of the deed seem to support the assumption that he deceased had kept his illness from his employer and his colleagues."

"It will take a number of days to examine the treatment related documents as well as pertinent witness statement. We will inform the relatives as well as the public as soon as there are any solid findings," he added.

Mr Lubitz has been accused of deliberately flying the aircraft into a mountainside shortly after preventing the captain from re-entering the cockpit.

All 150 on board the aircraft died in the crash.

German media has reported that he received treatment for a "serious depressive episode" six years ago during his training to become a pilot.

On Friday, Germanwings said it was setting up a family assistance centre in Marseille for relatives of those killed in the crash.

Spokesman Thomas Winkelmann said in a statement that "in these dark hours our full attention belongs to the emotional support of the relatives and friends of the victims of Flight 9525."

Some relatives took part in a memorial service on Thursday near the crash site in the French Alps.

German President Joachim Gauck also attended a memorial service in Haltern for 16 students and two teachers from the local high school who were killed.

It comes as police and rescue workers hunt for the aircraft's second black box on the fourth day of recovery operations at the scene of the crash.

Officials are searching the wreckage for body parts and DNA to try and identify the 150 people killed in the crash.

Some 75 German people were on board the aircraft, which was flying from Barcelona to Dusseldorf. At least 50 Spanish citizens were also on the flight, along with three Britons.

The second black box contains technical flight data.

Meanwhile the Transport Minister Paschal Donohoe says he expects there to be a review of Irish aviation regulations in light of the tragedy.

Mr Donohoe told Clare FM that Aer Lingus and Ryanair already have regulations in place insisting that two people are in the cockpit at all times.

He also insisted that flying is safe.