More than 750 historic artefacts are still unaccounted for, following yesterday's fire at the Cuming Museum in Walworth.
Around 500 items have been recovered from the building, some of which are badly damaged.
Among the objects still missing are two 19th century jars that were on loan from British Museum.
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A post-mortem report found no traces of drugs or alcohol, and the evidence suggests Simon Brown was not taking photos.
The masked men used an angle grinder to tear through the lock.
Doing as little as possible in the first minute helps people regain control of breathing and increases chances of survival, says the RNLI.