Detectives investigating the frenzied murders of two French students are questioning a 21- year-old man who was arrested early yesterday morning.

The suspect, who is known to local police, was arrested by murder squad detectives at 3.40am on a street close to the murder scene.

Investigators are unclear whether the arrested man is the same person seen running from the block of smart flats in New Cross, southeast London, shortly after it was set on fire and are still appealing for witnesses and information. Further arrests have not been ruled out.

Senior officers are working on the theory that Gabriel Ferez and his fellow postgraduate student Laurent Bonomo, both 23, may have been tortured for the pin numbers of their bank and credit cards, and are monitoring their accounts.

Two Sony PSP games consoles are missing, believed to have been stolen from the flat, and a black Packard Bell Easynote SB laptop was stolen from the address in a burglary six days earlier. The murder and the burglary may be linked.

Within hours of the arrest the parents of Ferez appealed to the killer to give himself up.

Françoise and Olivier Ferez said: “To those who committed this crime against our son and his friend we say: it is possible you did not anticipate how this might turn out. We plead with you to turn yourselves in to the police. You will not be able to live in hiding for ever.”

They added: “You may be scared and feel like a coward, but you must recognise this terrible mistake. Rest assured that we will not leave you in peace.

“Someone, somewhere must know something that will help to solve this terrible crime. It is too late for Gabriel, an angel who is now a victim after giving us 23 years of love and who was always ready to help others around him.

“Please help us to reveal the truth. Help us to know, to understand and to come to terms with our loss. We ask our friends: the British people, please help us. Gabriel had a sister and a young brother who are now crying from their loss.”

Police say that if the burglar was not responsible for the murders, he should come forward.The beaten and mutilated bodies of the bioengineering research students were found gagged and bound to chairs in the burnt-out remains of the ground-floor flat last Sunday evening.

Bonomo had been stabbed 196 times, including 80 wounds to his back. Possibly half the wounds had been inflicted after his death. Ferez suffered 47 wounds and his body had been badly burnt.

The rented flat had been doused with a fire accelerant, not yet identified, and then firebombed in a possible attempt to erase the evidence.

Although a botched robbery remains the strongest line of inquiry, Metropolitan police officers, who describe the victims’ characters as unimpeachable, are baffled by the brutal and frenzied nature of the crime.

Bonomo and Ferez, described by their tutors as among “the brightest of their generation”, had been in London since May having been selected for a three-month research project at Imperial College London. They would have returned home later this month.

At their home university, the prestigious Polytech Clermont-Ferrand in central France, their lives will be commemorated with a silent march tomorrow.

It could be several weeks before the bodies can be released because toxicology tests are continuing.

French newspapers have seized on the murders to depict London as lawless. Headlines reported the killings as a “massacre” and warned readers visiting the capital not to venture south of the Thames after dark. Le Parisien, a national daily, described French expatriates in London as being “in a state of shock”.

In Clermont-Ferrand, the headline in La Montagne, the local newspaper, read: “The ‘Frenchies’ of London are afraid”. An inside story noted the shock felt within London’s French community: “No paranoia, and no mass departure of course. But revulsion at the ordeal of the two Clermont students and a growing perception of the brutality of London life.”

One blogger on the Libération website wrote: “These things happen all the time in London. ‘Le stabbing’ is the fashion.” Another wrote: “When night falls, skinheads go looking for a fight with foreigners.”

Christian Laroche, a professor in the department where both men studied, said he would not hold London responsible: “I refuse to mix up such a horrible event and the place where it happened. It could happen anywhere. I’m not going to tell my students not to go to London. I’m not going to yield to that kind of psychosis.”

Additional reporting: Brendan Montague

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