This article is more than 11 months old

This article is more than 11 months old

UK police have been blamed for a cross-Channel farce that led to an innocent man being arrested and mistakenly identified as a fugitive wanted in connection with five murders.

In France “high level” sources told journalists that Interpol in London had alerted them that 58-year-old suspect Xavier Dupont de Ligonnès, would be on a flight from Paris to Glasgow this weekend.

French investigators have been trying since 2011 – without success – to establish whether Dupont de Ligonnès is alive, after the bodies of his wife and four children were discovered buried under the terrace of the family home in the French city of Nantes.

After the alleged tipoff, Scottish police arrested a man as he stepped off the flight. Le Parisien newspaper reported that Scottish officers then called their French counterparts to insist: “This is your man.”

In fact, the man was not Dupont de Ligonnès, but Portuguese-born Guy Joao, who lives in Limay, in the Yvelines, north-west of Paris, and who spent the night in custody. After DNA and fingerprint testing, Joao was released.

In a statement, Police Scotland said the man arrested at Glasgow Airport had been released: “He was held in police custody in connection with a European Arrest Warrant issued by the French authorities.

“Inquiries were undertaken to confirm the man’s identity. Following the results of these tests it has been confirmed that the man arrested is not the man suspected of crimes in France.”

On Saturday morning, as French investigators travelled to Glasgow, public prosecutor Pierre Sennès had urged the press to “exercise caution”, saying “verifications” as to the identity of the suspect were underway.

“Teams of detectives from the national service for the research into fugitives and from the Nantes police would be travelling to Glasgow on Saturday,” Sennès said.

However, the story, broken by Le Parisien on Friday evening and picked up by Agence France-Presse, which said it confirmed the identification of Dupont de Ligonnès with four separate police sources, spread.

Le Parisien newspaper, citing “high level sources” placed the blame for the “theatrical misunderstanding” firmly on the UK side, claiming Interpol’s London office had contacted the French authorities to alert them that the man thought to be Dupont de Ligonnès would be flying from Paris to Glasgow on Saturday using a passport stolen in 2014.

Le Parisian reported: “But another theatrical event happened Friday: the English authorities alerted the French to a change in the reservation of the suspect’s ticket, meaning he would actually take off this Friday at Roissy. With little time and with the impossibility to send a surveillance team, the French investigators asked their Scottish colleagues to go ahead and arrest the suspect as he got off the plane at Glasgow Airport. This is how, on Friday afternoon, Guy Joao was apprehended, while his Scottish wife waited for him in the arrival hall.”

Le Parisien added that “several high placed sources are categorical on one point ... Scottish police told us and they repeated it: this is your manHowever, despite several French demands, Scottish police refused to send them the fingerprints taken at Glasgow.”

Scottish police refused to respond to the French accusations when contacted by the Guardian.

The story of what became known as the “de Ligonnès affair” has puzzled and fascinated professional and amateur detectives, leading to genuine theories and conspiracy theories, many of them supported by members of the family.

Investigators have followed leads suggesting the family emigrated secretly to the US or Australia, but they insist Dupont de Ligonnès remains the prime suspect and the most likely scenario is that he killed himself after killing his family.

His wife, Agnès, 47, her eldest son, Arthur, 20, from her first marriage, Thomas, 18, and Anne, 16, were shot twice in the head. The youngest child, Benoît, 13, was shot three times in the head and twice in the thorax.

Detectives believe Dupont de Ligonnès killed Agnès and three of the children on the night of 3-4 April and Thomas the following evening.

The bodies were placed in jute sacks and covered in lime to speed up decomposition and disguise their smell.

Postmortem examinations found the five victims had been given sleeping tablets and were shot with a .22 long rifle. Dupont de Ligonnès had inherited a gun of the same make and calibre from his father three weeks earlier.

Since 2011, there have been more than 900 purported sightings of Dupont de Ligonnès reported to police, all of which have yielded nothing.