LONDON-- Red Bull Formula One team boss Christian Horner attended a hearing on Friday to answer allegations about his conduct that have cast doubt on his future and could overshadow the champions' car launch next week. Red Bull Racing and the Austrian energy drink parent company, who have not detailed the nature of the complaint, remained tight-lipped with representatives not responding to calls or emails. F1 insiders told Reuters they understood the hearing was held in London at an undisclosed location rather than the team's Milton Keynes factory. READ: F1: Christian Horner under investigation for 'inappropriate behavior' allegations Sky Sports television reported the meetin...Keep on reading: F1: Horner inquiry could drag on after initial Red Bull hearing