Relatives reveal heartbreak over Alps murders as prosecutors outline main lines of inquiry Meanwhile at a press conference in Annecy, prosecutor Eric Maillaud said that "the job, the family, Iraq" were the "essential" lines to be prioritised in the investigation. The latter has been at the centre of considerable attention and Mr Maillaud said a "specialised" team was tasked with examining Mr al-Hilli's links to the country. He said: "The fact that he was born in Iraq, that he had family in Iraq, of course that's something that is of interest and we are asking ourselves if there is a link between that and his death. There are specialised people as far as Iraq is concerned who are looking at it, in other words, people who know who to contact in order to be able to work with that country so, for example, we have a security attache we are working with. Mr Maillaud said the bodies of the four people killed in the attack had been returned to their families. He also confirmed that Mr al-Hilli's seven-year-old daughter, who has been in hospital after suffering serious head injuries, was still unable to speak to investigators about what happened. "I've read in many places that she is the key witness and of course she is the only person living who witnessed the attack," he said. We will talk to her but it is not on the testimony of a seriously injured little girl that the whole investigation can be based. He added: "She will, of course, be listened to very specifically, but her doctors have got to be able to help her try to get back to the best possible health, and eventually hope she will express herself." Mr Maillaud said she was a key witness - "the only person alive who actually could have seen something" - but warned that she was seven years old and had been "very damaged." Police have spent days searching the al-Hillis' home in Claygate, Surrey but have yet to announce any discovery there that could shed light on why the family was killed. French police have established that one gun was used for all 25 shots fired at the scene and also that the al-Hilli family changed campsites for an unknown reason two days before the attack. Mr Maillaud and judge Michel Mollin are to travel to London tomorrow for an update on progress on the other side of the Channel. The pair also plan to visit the family home. The prosecutor said four French investigators were in Britain and cooperation between French and British detectives was good. But he said there were "difficulties," particularly due to what he called the "language barrier." As well as searching the house and probing Mr al-Hilli's business affairs, British police have questioned his brother about a reported family dispute over money, which the brother denies. Mr Maillaud said 40 French officers were working on the complex case which has led to a flurry of theories relating to possible motives. But he gave no indication that French authorities were any closer to solving the murders, suggesting it could be years before answers emerge. Mr Maillaud said the large part of the investigation was taking place in the UK and that French authorities believe there could be a "great number of clues" in Britain. Mr Maillaud said investigators had no plans to travel to Sweden, where Mrs al-Hilli's mother Mrs al-Allaf was living. But he said police would interview a relative in the country, if it transpired that reports relating to his alleged history of violence proved to be correct.