BARCELONA, Spain — Doctors who treated Germanwings pilot Andreas Lubitz for depression and mental illness before he killed 150 people by crashing into the Alps last year refused to speak with French investigators who were trying to prevent a similar sequence from ever happening again, one victim’s father said Saturday. The French investigators told relatives at a meeting in Barcelona that the German doctors were not required to talk about Lubitz’s medical conditions under German privacy laws and they didn’t, even though the 27-year-old also died in the March 24, 2015, plane crash. The experts from France’s BEA crash investigation agency did obtain detailed German medical records about Lubitz but “they emphasized that the doctors, those who treated him, refused to give any information,” said Robert Tansill Oliver, who attended the Germanwings relatives’ meeting. The French investigators told the relatives that one of their safety recommendations would be a requirement that doctors provide authorities with information about pilots’ mental health issues. The BEA on Saturday declined to comment on the closed-door meetings with relatives, who were shown a slide show but given no written materials. The meetings Saturday in Barcelona and Bonn briefed the victims’ relatives about a BEA report being released today that is expected to make recommendations to help aviation agencies and airlines around the world prevent similar crashes.