( CNN ) -- For as long as eight hours , the small girl hid , unnoticed , in a car with the bodies of two British women and a man shot dead in foothills of the Alps in eastern France . Probably paralyzed by fear , the 4-year-old remained among the corpses as investigators waited for crime scene technicians to arrive so the car could be opened . She is now under police protection , as is an older girl , thought to be 7 or 8 years old , who was found injured near the car . She suffered a fractured skull and an apparent bullet wound to the shoulder . Prosecutor Eric Maillaud told reporters Thursday that investigators failed to notice the younger girl because she did n't move for hours as they waited for the forensic experts . She was hidden under baggage and the legs of one of the dead women in the car 's back seat . A thermal imaging camera failed to pick up her presence , Maillaud said . The child was `` probably terrorized , completely concealed , completely immobile amid the corpses , '' he said . Authorities have not identified the three Britons found dead on Wednesday in the car near Lake Annecy , a popular tourist spot in the Haute-Savoie area of eastern France . A fourth victim , a French cyclist found shot in the head near the car , has been named as Sylvain Mollier . British Prime Minister David Cameron said he and French President Francois Hollande discussed the `` terrible killings of ... the British family '' during a meeting Thursday in London . He promised British authorities will cooperate `` very closely with the French authorities '' to `` help those poor children '' and `` get to the bottom of what happened in this clearly very tragic and awful case . '' `` Both a French and a British family have been impacted by this terrible event , and we will do our utmost to identify the perpetrators , '' added Hollande in a joint press conference after the two leaders ' meeting . Maillaud , the French prosecutor , has called the shootings an act of `` extreme savagery '' but has declined to speculate on a motive . `` The scene is dramatic , it 's unusual -- it goes well beyond TV fiction , '' he said . Multiple bullet casings had surrounded the BMW when authorities came upon it , with bullet holes peppering its windows but none in the body of the car , according to the prosecutor . The driver and an older woman found dead in the car had been shot in the head , Maillaud said , `` and it was obvious that ( whoever ) did this wanted to kill . '' Autopsies are scheduled Friday and should reveal how the other passenger , a younger woman , died . The car was registered to a man with an Iraqi passport who was a naturalized British citizen and had lived in Britain since at least 2002 , he said . The passport was used when the visitors checked in to the campsite where they were staying , Maillaud said , but police ca n't yet confirm whether it belonged to the man who was found dead in the car . The man named in the passport was born in 1962 , the French prosecutor said . A Swedish passport found by investigators may belong to the older woman , he added . The victims are believed to be British nationals but may have held dual citizenship . Swedish Foreign Ministry spokeswoman Catarina Axelsson described `` the French information about the Swedish national ( as ) reliable , '' adding that authorities there were awaiting a `` final confirmation of the identity . '' DNA tests are being carried out to formally identify the victims . French and British news reports have identified one victim as Saad al-Hilli , an Iraqi-born engineer who lived in Claygate in Surrey , south of London , with his wife and two daughters . While CNN could n't independently confirm the identities of the victims , Surrey Police have said they are helping police in Annecy with their investigation into the killings , though they have n't given further details . Officers from Surrey Police were stationed Thursday outside the house identified by neighbors as that of Saad al-Hilli . Neighbor Jack Saltman , whose home backs onto the family 's garden , said al-Hill and his wife had come from Iraq `` many years '' ago and both spoke `` perfect English . '' `` They were a delightful family , '' Saltman said . The neighbor said al-Hilli 's wife , Iqbal , was a dentist and that the two daughters were `` absolutely beautiful . '' He had been asked to keep an eye on the house while his neighbors were away in France , Saltman said . An accountant for Saad al-Hilli , Julian Stedman , said the engineer had at least one business registered locally . Maillaud said the two children , who are British , are being kept under police protection in case of possible threats to their safety . `` You can imagine in an inquiry all possible scenarios can be investigated , including that someone wanted to get rid of additional witnesses , '' he said . The 4-year-old has only been able to tell police that she heard noise and screams and was afraid , he said . The older girl , who has head injuries , was hit `` extremely violently , '' he said . She has been placed in a medically induced coma and will have to undergo additional surgery , Maillaud said . The British ambassador to France , Peter Ricketts , told reporters in Annecy , `` I think it 's our joint conviction that we have got to do everything possible to find the perpetrators of this terrible crime . '' Asked about police 's failure to find the 4-year-old girl sooner , he said French authorities were doing a professional job . Maillaud recounted how the gruesome scene was discovered just before 4 p.m. Wednesday by another British man , a cyclist who was a Royal Air Force veteran with a holiday home in the area . The British man , who had been passed a short while earlier by the French cyclist found dead at the scene , discovered the BMW , its engine still running , in a parking lot in a forest used by people going on short walks . It is not regarded as a dangerous area or a common site of drug deals , according to the prosecutor . The injured girl was approaching the car and was about to pass out in front of the man , Maillaud said . He placed her in a safe position on the ground and called emergency services . The man then discovered the cyclist who had passed him earlier , dead on the ground in a corner of the parking lot . After walking round the car , the British man broke the driver 's side window and saw three people inside it , all also dead . Are you there ? Share your story . The girl who was wounded in the shooting was taken to a hospital in Grenoble . There was only one child car seat in the vehicle , which led officials to believe she was the only child present , Maillaud said . Authorities were alerted to the likely presence of a second child several hours later when they spoke to people at the campsite where the victims had been staying , Maillaud said . When they searched the car again , by then late at night , they found the 4-year-old girl under the younger woman 's legs . After being checked over for injuries , she was taken to a children 's psychiatric unit , where a nurse remained with her overnight , he said . The girl , who was not physically harmed , will be questioned only with British consular officials present , Maillaud said . `` Her life is not in danger , but she has experienced something awful , '' he said . Mollier , the French cyclist , had lived in the region for 20 years and was on paternity leave , BFM-TV reported . Maillaud said the man 's wife had gone to the police when he failed to return as expected from his bike ride . He was then identified as the slain cyclist . The British Foreign Office said it was looking into the shooting . `` We are aware of this tragic incident near Lake Annecy . We are working with the French authorities to confirm that British nationals were involved , '' a Foreign Office spokesman said . `` Thoughts are with the friends and family . There are currently consular officials on the ground and providing consular assistance . '' More from CNN Justice : . Turkish woman awaits trial after beheading her alleged rapist . 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NEW : Britain 's prime minister laments the `` terrible killings of ... the British family '' Three of the four adults killed , one a cyclist , were shot in the head , a prosecutor says . The other two victims died from gunshot wounds to their legs and arms. A younger girl was found alive and unharmed in the car where three adults were killed .