Laurent Bonomo and Gabriel Ferez, both 23, were stabbed 243 times, tied to chairs, gagged and burnt in one of the most "frenzied and brutal" murders ever investigated by Scotland Yard.
The strongest line of inquiry is that they were targeted by a burglar at the flat in New Cross who had raided the flat six days earlier.
Scotland Yard chiefs are shocked that such a level of violence could be used in the burglary of two Sony PSP consoles, worth around £100 each.
They are also investigating whether the young scientists' cash cards are missing, and fear that they may have been tortured and repeatedly stabbed until they revealed their PIN codes.
Detectives are linking the stabbing to a previous raid, six days before the murder, in which a laptop computer was stolen. They are also investigating whether a set of keys was taken, which would explain why there was no forced entry prior to the attack on Sunday.
Det Chf Insp Mick Duthie who is leading the investigation, said: "The search of the address is not yet completed, but we have established that two Sony PSPs are missing and believe they were taken during the incident on Sunday when the two men were killed.
"We are keen to hear from anyone who has recently been offered a laptop and two personal game consoles, or knows someone who has unexpectedly come to have them.
"A black Packard Bell laptop was taken during a burglary that took place between 5 and 6 am on the morning of 23 June, 2008. Someone entered the living room of 12 Sterling Gardens and stole the computer.
"Laurent Bonomo said he was in the shower when he heard a suspicious noise. He found the window of his living room forced open and his laptop was stolen."
The murder scene was decimated after the victims, described as "two of the brightest students of their generation", were doused in an accelerant and the bedsit was firebombed in an attempt to hide the evidence.
Officers are hunting a white man seen running from the rented bedsit moments after it exploded. They have had 25 calls from members of the public since putting out appeals, many of which refer to the fleeing white man.
However police have not rules out the possible involvement of at least one other killer.
Meanwhile, a relative of Mr Bonomo visited the scene today.
Leo Bonomo, 51, Laurent's third cousin, laid flowers and said: "Obviously I am completely shocked. I didn't really know Laurent, but we're connected through family so I wanted to pay my respect.
"They were obviously very talented boys. I am saddened not only that this has happened to someone, but that it has happened in such an incredible way.
"Our family in Europe are also very shocked. There are slightly different cultures between here and mainland Europe. Personally I think it's getting terrible over here. Knife crime is getting ridiculous and I know that the Government are trying their best but a deterrent punishment is really the way to go.
"I think this is a general problem throughout the country, but I think it is getting especially bad in London compared to somewhere like New York."
Mr Ferez's sister Hélène, 19, described the moment she was told of his death as "the worst experience of my life."
"Nothing can change what's happened, but I want to know who did this, and why. I will do absolutely anything to find the person or persons who did it," she said in a message posted on social networking website Facebook.
"He was an exceptional boy who would have done anything for anyone. He was incredibly intelligent, proud and enormously capable. He didn't deserve this and neither did Laurent."
