The Federal Magistrates' Court has found Commonwealth Bank did not breach a former state sales manager's employment contract when it dismissed him over an alleged incident with a female probationary employee he was mentoring.The bank's WA sales manager visited Sydney in December 2006 to mentor the employee, whom he hadn't met before.He took her to lunch at the Blues Point Cafe at McMahon's Point, where they also drank wine.After lunch, they were due to attend a meeting at a CBA office in the Sydney CBD, but were running late, and instead dialled-in to the meeting from the sales manager's room at the Radisson Plaza Hotel, where they drank more wine during and after the telephone conference.The probationary employee claimed that she went to the bathroom and on her return, "suffered from a sudden onset of extreme lethargy and blurred vision". She said in a statement provided to the bank that she then lay down on the bed at his suggestion and had no clear recollection of events thereafter.The following day, the employee observed "severe bruises" on her body. She attended the sexual assault service at Royal North Shore Hospital for a medical examination, and was told by a physician and psychologist "it was likely I had been the victim of an attempted rape after being drugged" and the bruises were consistent with being inflicted by a man's hand.The sales manager strenuously denied the allegations.The employee lodged complaints with her employer and the NSW Police.Following investigations by the bank's executive manager, strategic HR support for the premium business services, the bank wrote to the manager setting out the allegations and told him the bank had determined, on the balance of probabilities, that he had breached the bank's statement of professional practice and his employment contract by committing serious misconduct.The bank advised its state sales manager that it was considering terminating his employment, but was giving him the opportunity to provide further representations and material in his defence.After reviewing additional material from the manager and a report from his subordinate the bank's executive general manager, corporate financial services, dismissed the sales manager in February 2007, more than two months after the original complaint.Federal Magistrate Toni Lucev rejected the sales manager's challenge to the competency and impartiality of CBA's investigating officer.He found that CBA conducted the investigation fairly and properly and in keeping with the principles for such processes under the bank's Fair Workplace Policy. The investigation provided both procedural and substantive fairness, he concluded.The magistrate said there was "no doubt" that sexually or indecently assaulting a fellow employee is serious misconduct warranting summary dismissal without notice."It is such a fundamental breach of an employee's duty, particularly in circumstances where the employee is a senior employee and mentor to the employee who has been assaulted,"  he said.The bank owed the employee a duty of care to ensure she came to no harm or injury, "where as a consequence of her incompetent state she was manifestly vulnerable".On that basis, the magistrate ruled, the CBA