Divorced British father 'in custody battle' arrested after French police find bodies of his son and daughter with their throats cut Five-year-old girl and 10-year-old boy found dead in father's apartment Believed to be first weekend father was allowed sole custody of children Police alerted by mother who bumped into him in lobby on Saturday He was arrested by police on suspicion of murder today A divorced British father involved in a bitter child custody battle was being held by French police today after the bodies of his son and daughter were discovered with their throats cut. The 48-year-old man's ex-wife found her children's lifeless corpses after bumping into him in the lobby of apartment block in a suburb of Lyon on Saturday. The couple, who have not been named, were said to have been involved in the custody dispute following their divorce two or three years ago. 'Murder scene': The second-flat apartment in the Lyon suburb of Saint-Priest where the children were found Family home: The flat is believed to have been where the family of four lived before the divorce The children, a five-year-old girl and 10-year-old boy, were in the care on their mother, an accountant, who went to live outside Lyon. It is thought that they were visiting their father for the weekend, staying at his apartment in the Saint-Priest area of outer Lyon. After the mother raised the alarm, the man was arrested in the eighth arrondissement of Lyon on suspicion of having murdered his children. Ahmed Benguedda, a neighbour of the man, said the couple had divorced "two or three years ago." Mr Benguedda said the man was currently out of work and had not sold the flat, where the family used to live together. 'Homicides': Police sealed the apartment after finding the bodies Investigation: 'Homicides' translates to 'murder scene' 'The people who live here are all in a state of shock,' he said. He added that his seven-year-old daughter used to play with the two victims, whom he described as 'well adjusted'. This morning the word "Murder Scene" was written on a police notice on the door of the apartment, while the father was being held in a police cell in the centre of Lyon. A judicial source said that this weekend was the first ever that the man had been allowed custody of the children. The mother was said to have been worried when he did not return them as planned, and this is the reason she went round to the second floor flat late on Saturday afternoon. "It was the first time since the divorce that the man was allowed to be alone with the children," said the source. 'Murder': The two children were found dead in Lyon, France (stock photo) The mother was said to be too traumatised to talk to police, but "her testament will prove crucial," the same judicial source told AFP, France's national news agency. Investigators will want to know who gave the father legal authority to look after the children. The mother, an assistant accountant, had won custody of the children following her divorce and had left to live in Isere, a region to the south-east of Lyon, while the unemployed father continued to live in the flat, according to a Parisien paper.