One of the two French research students found dead in a burnt-out London flat had been stabbed 196 times, the detective leading the murder investigation said today. His friend had 47 separate injuries.

The deaths of Laurent Bonomo and Gabriel Ferez, both aged 23, came as a massive shock to their families and fellow students at the Polytech in Clermont-Ferrand, central France, where both studied bio-engineering and where Mr Bonomo had recently been student president.

The horrific nature of the attack against them shocked even experienced detectives. "I have never seen injuries inflicted to bodies like this before," Detective Chief Inspector Mick Duthie told a press conference at Scotland Yard.

Mr Duthie told The Times that the two men had been playing a computer game before the attack in the flat at Sterling Gardens, New Cross, which had been rented by Mr Bonomo.

Bound up by their attacker or attackers, they received multiple stab wounds in the head, neck, back and torso.

Mr Bonomo was stabbed 196 times, Mr Duthie said. Almost 100 of those wounds were inflicted to his back after his death. Mr Ferez was stabbed 47 times.

The two were talented and committed students on a three-month research placement at Imperial College, London, who had impressed colleagues with their maturity. They were enrolled on the university's research opportunities programme, which allows students who have not yet graduated from their Masters degrees to take part in research.

An Imperial College spokesman said that Mr Bonomo was studying a parasite which can spread from cats to human foetuses. Mr Ferez’s research was into bacteria which create ethanol for use as fuel.

Speaking at his press conference, Mr Duthie said that a fire accelerant had been sprayed around the flat before it was set alight. A white male seen running away from the area is so far the only suspect.

"Members of the families have travelled from France. I met them yesterday and this morning they had to go through the gruesome task of identifying their sons," he said. Mr Bonomo was originally from Aix en Provence; Mr Ferez from near Amiens.

The one-bedroom ground floor flat of a three-storey terraced block is situated in a pleasant cul-de-sac in a relatively leafy part of New Cross which residents described as calm and peaceful.

Police have cordoned off the flat, with scaffolding and tarpaulins erected across the downstairs bay window and kitchen window. A police officer stood guard today at the entrance to the block.

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