A police officer has been served with a misconduct notice as part of an investigation into the sudden death of a 24-year-old shortly after he was released from custody. The Independent Office for Police Conduct (IOPC) said that the South Wales police officer was in the back of a van with Mohamud Mohammed Hassan after his arrest in January at his Cardiff home on suspicion of breach of the peace. Hassan complained of having a fit and suffering a migraine, and displayed signs of experiencing pain during the journey, but was held in custody overnight. He died shortly after his release at 8.30am the next day. The IOPC said that the notice indicated an investigation was under way into whether the officer failed to pass on information about Hassan’s condition to colleagues at the police station. If the officer is found to have breached professional standards after an investigation, they could be given a written warning. The notice comes as part of a wider IOPC investigation into Hassan’s death using body-worn video and CCTV footage, amid allegations that he suffered a series of injuries while in custody. The watchdog said last week that preliminary indications were that there was no physical trauma injury to explain the cause of death and toxicology tests would be needed. It emerged last week that an investigator told Hassan’s family that Hassan had come into contact with more than 50 police officers during the final hours of his life. Family lawyer Hilary Brown said then: “They are understandably disturbed by it. There are allegations of excessive force and to hear that Hassan was subject to this level of police contact has been really upsetting.” He said the family also felt it was unfair that they had been denied further information about the nature of the contact. The IOPC director for Wales, Catrin Evans, said that a decision over whether the officer had a disciplinary case to answer would come at the conclusion of the investigation. “We are continuing to analyse the footage and piece together other evidence, and we are looking at all the interaction police had with Mr Hassan over the weekend of his death,” she said. “We have advised Mr Hassan’s family and South Wales police that we have [served a disciplinary notice] for one officer over possibly not passing information about Mr Hassan’s welfare to the custody sergeant on duty. We keep misconduct notices under review during the course of an investigation.”