SISTERON, France (AP) — The father of the German co-pilot accused of crashing a passenger plane in the French Alps was distraught with grief over his son's death and over what he may have done, the mayor of a town close to the crash site said Saturday.

Bernard Bartolini, the mayor of Prads-Haute-Bleone, said he met the father of Andreas Lubitz at a memorial late Thursday for relatives of those who died in the crash.

"He was distraught with grief. He was a completely broken man who is carrying all the responsibility of this drama on his back," Bartolini said on BFM-TV. "He lost a loved one, but also because his son is perhaps the (cause) of this tragedy."

Hours before the memorial, French prosecutors announced that they believe Lubitz deliberately slammed the Germanwings flight into a mountain on Tuesday, killing all 150 people aboard.

German prosecutors, who have been trying to determine what caused Lubitz to take such a devastating decision, met with their French counterparts Saturday to discuss the preliminary findings of their investigation.

Duesseldorf prosecutors say Lubitz hid evidence of an illness from his employers — including a torn-up doctor's note that would have kept him off work the day authorities say he crashed Flight 9525.

Searches conducted at Lubitz's homes in Duesseldorf and in the town of Montabaur turned up documents pointing to "an existing illness and appropriate medical treatment," but no suicide note was found, said Ralf Herrenbrueck, of the Duesseldorf prosecutors' office.

Prosecutors didn't specify what illness Lubitz may have been suffering from, or say whether it was mental or physical. German media reported that the 27-year-old had suffered from depression. The New York Times and Germany's Bild am Sonntag weekly also reported Saturday that Lubitz had eye problems.

Duesseldorf University Hospital said Friday that Lubitz had been a patient there over the past two months and last went in for a "diagnostic evaluation" on March 10. It declined to provide details, but denied reports it had treated Lubitz for depression.

Colleagues and acquaintances described Lubitz as an affable man in good physical health who was focused on a career as a pilot.

Frank Woiton, another Germanwings pilot, said Lubitz told him he wanted to become a long-distance pilot and fly Airbus A380 or Boeing 747 planes.

Woiton, who like Lubitz comes from Montabaur, said he met Lubitz for the first time three weeks ago when they flew Duesseldorf to Vienna and back together.

Woiton told German public broadcaster WDR on Friday that Lubitz didn't stand out and appeared like any other colleague. Lubitz "flew well and knew how to handle the plane," he said.

Lubitz also frequented a gliding club near the crash site as a child with his parents, according to Francis Kefer, a member of the club in the town of Sisteron.

Kefer told i-Tele television that Lubitz's family and other members of the gliding club in his hometown of Montabaur came to the region regularly between 1996 and 2003.

The crash site is about 50 kilometers (30 miles) away from the Aero-club de Sisteron glider airfield.

Officials at the club wouldn't comment Saturday.

The area, with its numerous peaks and valleys and stunning panoramas, is popular with glider pilots. In the final moments of the Germanwings flight, Lubitz overflew the major turning points for gliders in the region, flying from one peak to another, according to local glider pilots.

A special Mass was being held Saturday in the nearby town of Digne-les-Bains to honor the victims and support their families.

Bishop Jean-Philippe Nault led the Mass, attended by about 200 people from the surrounding region, deeply shaken by the crash. It was the deadliest crash on French soil in decades.

The plane shattered into thousands of pieces, and police are toiling to retrieve the remains of the victims and the aircraft from a hard-to-reach Alpine valley near the village of Le Vernet.

Following the crash, the European Aviation Safety Agency issued a new recommendation that all airlines in Europe should require two people in the cockpit at all times during flight. If one of the pilots leaves the cockpit — only allowed during the cruising stage — then a flight attendant needs to take his or her place.

Ilias Maragakis, a spokesman for the agency, said EASA's recommendation isn't binding but airlines generally follow them. Once the crash investigation has been completed, the agency may review and amend its compulsory regulations and requirements.

Questions have been raised about what airlines should do to ensure their pilots are fit to fly.

Germanwings, the Lufthansa subsidiary that Lubitz joined in 2013, declined Saturday to comment when asked whether the company was aware of any psychological problems he might have had. But it said he had passed all required medical check-ups.

Aviation experts say those checks are stringent but focus mainly on physical health. A pilot's mental state is usually only assessed before companies decide whether to admit them to a training program — and even then a determined person could hide a latent problem.

"The test that will get you into a Lufthansa flight training program is a very hard test and this is why most people who get into those pilot classes will train for those tests," said David Hasse, the editor-in-chief of German aviation website airliners.de.

"There are coaching facilities, companies that are specialized in training people on how to pass those tests, and they will also advise you on how to behave in the psychological tests."

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David McHugh in Montabaur, Germany; Nicolas Garriga in Digne-les-Bains, France, and Elaine Ganley in Paris contributed.