The father of missing Swiss twins wrote to their mother to say he had "killed them", shortly before he committed suicide in southeastern Italy, Swiss police said on Friday.
"The last envelope dated February 3 contained a letter in which the father said he killed the two girls, saying he was in Cerignola where he was about to kill himself," Vaud regional police spokesman Jean-Christophe Sauterel said, Expatica France reports.
Matthias Schepp sent the note to wife Irina Lucidi before he was hit by a train in Italy last week.
Police across Europe have been searching desperately for the couple's six-year-old daughters Alessia and Livia since they failed to return to the family home in Lausanne, Switzerland, on January 30.
The contents of the note were not made public immediately by police hunting the girls for fear of discouraging potential witnesses to come forward.
Police revealed that the Canadian-born man consulted websites on travel to Corsica as well as those detailing suicide, poisoning and firearms, shortly before the girls' disappearance, according to NEWS.com.au
The latest evidence emerging Thursday added weight to a French prosecutor's theory that Schepp either threw the girls overboard during the overnight ferry ride, perhaps after drugging them, or killed them on the island.
"There are lots of theories and the saddest and most tragic is that he ended the lives of the little girls, that he killed them, either on the ferry journey from Marseille to Propriano, or after," Jacques Dallest said.
Several witnesses saw six-year-old sisters Alessia and Livia on the ferry, but none have come forward to say they saw them after it arrived in Corsica.
Schepp had been distraught over the 2010 separation from his ex-wife, Irina Lucidi. Her brother, Dr. Valerio Lucidi, said earlier this week that his brother-in-law took off with the girls in a moment of "madness," Vancouver Sun informs.