A criminal investigation has been launched into a mix-up at a mortuary where the body of a Falklands war veteran who died in police custody turned up in a mortuary more than a decade after he was believed to have been buried. Ex-paratrooper Christopher Alder, 37, choked to death while handcuffed and lying on the floor of a police station in Hull, in the early hours of April 1 1998. It now appears a Hull pensioner called Grace Kamara was buried in his place in 2000. Mrs Kamara is understood to have died from natural causes in 1999 but her burial was delayed and finally scheduled for Friday. It appears the blunder was only discovered because her friends and family asked to see the body and Mr Alder's remains were found in its place in the mortuary. Yesterday Nicola Yates, chief executive of Hull City Council, apologised and launched an investigation. She said: 'As chair of the multi-agency group dealing with the tragic circumstances around Grace Kamara and Christopher Alder, I have requested that the police undertake a criminal investigation into this extremely distressing case. 'As I said last night, I am appalled and distraught at what we have learned and my first priority has been to make sure the families involved are kept informed and given the necessary support. 'It is vital that the families and the public get a clear view of the facts and understand what happened. A thorough police investigation will make sure this happens. 'Now that the police are carrying out a formal investigation it would be inappropriate for me to comment further. ‘I recognise that this has been very traumatic for everyone involved and I again offer my sincere sympathies to the families.' Humberside Police's chief constable Tim Hollis said the investigation will be carried out by the South Yorkshire force due to the sensitive history of the case. Mr Hollis said: 'Whilst the role of the police is to provide investigative support to the respective authorities I am, naturally, mindful of the strong association of Humberside Police with Christopher Alder's name and his sad death. 'It is, therefore, my decision to invite South Yorkshire Police to provide a team of officers to undertake any necessary investigation into the circumstances that have come to light. 'On a personal note, my thoughts are with the family of Mrs Kamara who, at this time, still do not know the whereabouts of her body and to Christopher Alder's family who have now been informed that Christopher's body was not buried, as they believed, in November 2000. 'Officers from South Yorkshire Police will conduct the investigation, on behalf of Humberside Police. 'This investigation will examine the circumstances surrounding the retention and safe keeping of the bodies of Christopher Alder and Grace Kamara and their subsequent release for interment.' Mr. Alder's sister Janet expressed her shock over the mix-up branding it 'disgusting'. The 49-year-old said: ‘[Police] told me that in 1999 a woman called Grace Kamara, who was about 60, died from a heart attack. She was kept in deep freeze because her family, who all live in Nigeria, were asking for repatriation.’ Miss Alder added: ‘The undertakers went to get the body and it was then they found it wasn’t Grace, it was a man. ‘It’s just unbelievable – the police even said to me that they can’t say for sure that it was Grace that was buried in Christopher’s grave. I don’t know what to believe.’ Miss Alder has been told by officers that in 2000 the Hull mortuary where her brother’s body was kept had been moved to an unknown, temporary location. A year later it was moved permanently to Hull Royal Infirmary. Miss Alder added: ‘I want to know what’s happened to Christopher’s body all these years. ‘It’s like they just went into the mortuary, saw a black person and said “send this one out”.’