Xavier Dupont de Ligonnès, a Frenchman who is suspected to have killed his entire family in 2011 and has been on the run since, was arrested in Glasgow on Friday, AFP reported, citing police sources.
Dupont de Ligonnès had disembarked from a flight from Roissy-Charles de Gaulle airport, near Paris, AFP reported.
Dupont de Ligonnès, 58, had been noticed by the police at Roissy-Charles-de-Gaulle, but the police did not have time to act before the flight's boarding and instead warned Interpol, according to AFP.
"On Friday, 11 October 2019, a man was arrested at Glasgow Airport and remains in police custody in connection with a European Arrest Warrant issued by the French Authorities", a Police Scotland spokeswoman told Euronews.
Dupont de Ligonnès was wanted in France for the murder of his wife Agnès, 48, and his children, Arthur, 21, Thomas, 18, Anne, 16, and Benoît, 13, whose bodies, as well as those of the family's two dogs, had been discovered buried in the garden of the family house in Nantes, on 21 April 2011.
He was travelling under a false name, but his fingerprints betrayed him. He opposed 'no resistance' to his arrest, according to French newspaper Le Parisien, which broke the news.
The murders, known as the "Nantes slaughter", deeply shocked France at the time. Dupont de Ligonnès had disappeared before his family's bodies were found, and the murders had never been solved.
Police found a message he had sent in 2010 in which he had said he wanted to kill his family.
According to the AFP quoting a source close to the case, Dupont de Ligonnès travelled on a French passport that was stolen in 2014, and had "probably spent a part of his time on the run in the UK".
Before the murders, Dupont de Ligonnès had told neighbours and his children's schools that he was a secret agent and that the family was leaving to join a witness protection scheme.
He was last seen in April 2011, appearing on the 14th on a CCTV video as he withdrew money, and on the 15th as he left a hotel. His wife and children's bodies were discovered six days later.
His arrest followed an "anonymous denunciation", AFP reported. Le Parisien reported that he had been living in Scotland for some time.