As two talented biochemistry students and close friends, Laurent Bonomo and Gabriel Ferez had come to London to develop their skills as specialists in infectious disease and environmental engineering.
Instead the two became the victims of an attack that, even by the standards of a city battling against the blight of knife crime, is among the most horrific in living memory.
The bodies of Mr Bonomo and Mr Ferez, both 23, were found late on Sunday evening, bound, gagged and with hundreds of stab wounds and other injuries. They had been tortured and beaten repeatedly with a blunt instrument.
Yesterday officers described the killings, which took place in Mr Bonomo’s flat in southteast London, as the most vicious they had seen.
“This was a frenzied, brutal and horrific attack - I have never seen injuries inflicted to bodies like this before,” Detective Chief Inspector Mick Duthie, of the Homicide and Serious Crime Command, said yesterday as he called for public help in finding the killer, or killers.
“Everyone working on this case, including myself, senior detectives and support staff, has been deeply shocked by what we have seen.”
Officers admitted yesterday that they were at a loss to explain so incomprehensible a crime. Theories include a burglary gone wrong, a ritualistic killing or a case of mistaken identity. All police could confirm was that it was not suspected of being a professional hit, simply on the ground of the sheer, extraordinary, brutality of the killings.