MONTABAUR, Germany (AP) — Germanwings co-pilot Andreas Lubitz appears to have hidden evidence of an illness from his employers, including having been excused by a doctor from work on Tuesday, the day authorities say he crashed a passenger plane into a mountain, prosecutors said.

The evidence came from searches of Lubitz's homes in two German cities as authorities sought an explanation of why he locked himself into the cockpit and crashed the Airbus A320 into the French Alps, killing all 150 people on board.

Torn-up sick notes for the day of the crash "support the current preliminary assessment that the deceased hid his illness from his employer and colleagues," Duesseldorf prosecutors' office spokesman Ralf Herrenbrueck said Friday. Such sick notes from doctors excusing employees from work are common in Germany, even for minor illnesses.

Prosecutors didn't say what type of illness — mental or physical — Lubitz may have been suffering from. German media reported Friday that the 27-year-old had suffered from depression.

A Duesseldorf hospital confirmed Friday that Lubitz had been a patient there over the past two months. Duesseldorf University Hospital said he last came to the hospital for a "diagnostic evaluation" on March 10. It declined to provide details of his condition but denied reports that it had treated Lubitz for depression.

Investigators removed multiple boxes of items from Lubitz's apartment in Duesseldorf and his parents' house in Montabaur, near Frankfurt.

Herrenbrueck said the medical documents found indicated "an existing illness and appropriate medical treatment" but no suicide note was found. He added there was no indication of any political or religious motivation for Lubitz's actions.

Neighbors described a man whose physical health was superb and race records show Lubitz took part in several long-distance runs.

"He definitely did not smoke. He really took care of himself. He always went jogging. I am not sure whether he did marathons, but he was very healthy," said Johannes Rossmann, a neighbor a few doors away from Lubitz's home in Montabaur.

People in Montabaur who knew Lubitz told The Associated Press they were shocked at the allegations that he could have intentionally crashed the plane, saying he had been thrilled with his job at Germanwings and seemed very happy.

Germanwings and its parent company Lufthansa declined repeated requests to comment Friday on the new information about Lubitz.

A German aviation official told the AP that Lubitz's file at the country's Federal Aviation Office contained an "SIC" note, meaning that he needed "specific regular medical examination." Such a note could refer to either a physical or mental condition, but the official — who spoke only on condition of anonymity because he was not authorized to release the information, said the note does not specify which.

German news media have painted a picture of a man with a history of depression who had received psychological treatment, and who may have been set off by a falling out with his girlfriend. Duesseldorf prosecutors, who are leading the German side of the probe, refused to comment on the anonymously sourced reports.

Lufthansa CEO Carsten Spohr has said there was a "several-month" gap in Lubitz's training six years ago, but would not elaborate. Following the disruption, he said, Lubitz "not only passed all medical tests but also his flight training, all flying tests and checks."

The U.S. Federal Aviation Administration had issued Lubitz a third-class medical certificate. In order to obtain such a certificate, a pilot must be cleared of psychological problems including psychosis, bipolar disorder and personality disorders. The certificate also means that he wasn't found to be suffering from another mental health condition that "makes the person unable to safely perform the duties or exercise the privileges" of a pilot's license.

But experts say it's possible that someone with mental health problems could have hidden them from employers or a doctor without specialist training.

"It's a high-stakes situation for pilots because they know if they give the wrong answer, they could lose their license," said Dr. Raj Persaud, fellow of Britain's Royal College of Psychiatrists.

Doctors or psychiatrists in Germany are obliged to abide by medical secrecy unless their patient explicitly tells them he or she plans to commit an act of violence.

The president of the German pilots union Cockpit said medical checkups are done by certified doctors and take place once a year.

"At the moment all the evidence points clearly in one direction and it's the most likely scenario, there's no doubt about that," Ilja Schulz told The Associated Press. "But all the pieces must be put together, to see whether there were any other factors that played a role, or not. Only then can you draw lessons."

In France, police working at the Germanwings crash site said they had recovered between 400 and 600 pieces of remains so far from the 150 people who died.

Speaking from the French Alps town of Seyne-les-Alpes, Col. Patrick Touron of the gendarme service said "we haven't found a single body intact."

He also said DNA samples have been taken from objects provided by the victims' families — such as toothbrushes — that could help identify the victims. Touron also said jewelry and other objects could help in the identification process.

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Frank Jordans reported from Berlin. Associated Press Writers Joan Lowy in Washington, Maria Cheng in London, and David Rising and Geir Moulson in Berlin contributed to this report.