Two people voluntarily went to Wembley Police Station today to assist police investigating the gas explosion in Stanley Road, South Harrow, that left one man dead.
Emmad Qureshi, 26, was killed by a wound to the neck when three neighbouring houses blew up on the evening of May 7 2008.
Heroic passers-by had to drag injured people from the rubble, while families left temporarily homeless.
The latest development in the case comes as the Observer reported a few weeks ago that a special forensics report into the gas piping components removed from the house at the centre of the explosion was due to be received by detectives soon.
It was likely to indicate whether any criminal charges should arise from the evidence.
Harrow Police have not released any further details about the pair or explained how they are co-operating with the case. There have been no arrests.