An elderly flautist was at the centre of a police hunt last night after she vanished while possibly taking her instrument to a man to be cleaned.There have been no sightings of 78-year-old Maja O’Brien since she left her home in Oxford riding her purple bicycle and carrying her prized flute.Extensive searches for the keen swimmer have failed to produce any clues to her disappearance and fears were growing for her safety after it was believed she may have planned to take her musical instrument to an Eastern European man she knew, to have it professionally cleaned.Detectives said that her disappearance is “totally out of character” as they appealed to find her mystery acquaintance. She is believed to have left her home between around 5am and 9am on Thursday. Police released a photo of a bike similar to the one Ms O’Brien was riding when she went missingCredit:Thames Valley Police/Thames Valley Police Detective Inspector Jonathan Capps, Investigating officer with Thames Valley Police, said: “Maja is a keen flute player and we think she has taken her flute with her.“It is possible that Maja was on her way to meet an acquaintance who cleans musical instruments.”Unfortunately we don’t know the identity of this person but we believe they are a man and may originally be from Croatian or Eastern Europe. “If you believe you are this man, or you know who he is please contact police so we can understand if Maja had arranged to meet on Thursday. “Further, I would also appeal to any of Maja’s other friends to come forward if they had arranged to meet her on Thursday.”Ms O’Brien is a psychotherapist and published author on the subject. She is believed to be an amateur flautist.Her daughter, Petra O’Brien, who lives in London, tweeted a photograph of her and her mother today saying: “Happy Mother’s Day to all the mothers out there. This ones for my mum.”Detective Inspector Capps said that Ms O’Brien is around 5ft 6ins tall, of average build, with short grey hair and brown eyes.She is known to frequent Hinksey Park, Oxford City centre and the Four Pillars swimming pool, and residents will have seen searches in these areas, he added. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.