Mother fails to find missing Swiss twins in Corsica

"I still hope that my daughters are alive because they were seen alive in Corsica," their Italian mother Irina Lucidi said in emotional remarks to reporters in the Corsican city of Ajaccio.

"I want to renew my appeal to all the witnesses, to all the people who could have seen my girls in Corsica or on the continent (France) or in Italy," she said before leaving the French Mediterranean island aboard a private jet.

On their arrival earlier in the day, Lucidi and her brother immediately boarded a helicopter to overfly areas which the father mentioned in letters he sent before he died.

"We toured the island, we saw lots of sites," Lucidi said, describing the day as "long and difficult."

The helicopter flew over a number of areas from the island's southern tip to Cap Corse in the far north, tracing the itinerary the family had taken in 2008, along with areas cited by people who said they thought they had seen the father and the girls.

Matthias Schepp confessed in one of the letters to his estranged wife killing six-year-old Alessia and Livia Schepp before he threw himself under a train in Italy.

Swiss, French and Italian police have been searching for signs of the twins after Schepp, a Canadian-born Swiss, failed to return them to his wife on January 30 after picking them up two days earlier for the weekend.

Four days later he flung himself under a train in southern Italy, in apparent desperation at his separation from his wife and a custody dispute over the daughters.

The parents were a high-flying couple who worked for the tobacco giant Phillip Morris and who had separate homes in the quaint village of Saint-Sulpice on the shores of Lake Geneva in Switzerland.

Hope of finding the girls alive faded after the ANSA news agency cited relatives describing the chilling contents of a postcard and letters Schepp sent to Lucidi before he took his own life at the end of a dash through Switzerland, France and Italy.

"I have already killed the girls. They did not suffer and now they are resting in a tranquil place," the 43-year-old was quoted as saying in his last letter to Lucidi.

"I wanted to die with my daughters but it didn't happen that way. Now I will be the last to die," he reportedly wrote. "You will not see them again."

Investigators discovered after examining his computer that Schepp had consulted websites on suicide, poisoning and firearms before his final turn to look after the girls.

Lucidi's family have said Schepp suffered from a split personality.

Swiss newspaper 24 Heures reported he had been receiving psychiatric counselling, although there were no signs he presented a danger for his daughters.

French police were joined by Swiss colleagues on Saturday in Corsica, a popular tourist destination which Schepp had previously visited both on holidays and on work trips.

He and the girls were last seen on a ferry from mainland France to the island on 31 January but there has been no confirmed trace of the twins since that date.

Police have been scouring the island between Propriano in the southwest, where he arrived with the twins, and Bastia in the northeast, from where he left on a ferry, apparently alone in his black Audi 6 car.

Italian police were meanwhile concentrating their hunt on a canal not far from the station at the southern town of Cerignola, where he committed suicide.

They were acting on the assumption that Schepp threw away the satellite navigator from his car before he killed himself, ANSA said.

If found, it could enable them to retrace his route since he left Saint-Sulpice on January 28.