Detectives investigating the East Croydon sorting office rave where teenager Rio Andrew died have arrested two men and raided two addresses.
The raids in Poplar, east London, and West Horsley, Surrey, this morning led to two men in their 20s being arrested for drugs and licensing offences.
They are both in custody at a south London police station.
Detective Chief Inspector Sian Thomas, from Croydon CID, said: "There are a number of ongoing investigations into the events linked to the illegal rave in East Croydon and we will continue to pursue those involved in any aspect of criminal activity that took place that night.
"Immediately after the event, we made it clear that we were determined to pursue those who were involved in organising the illegal event, and we remain committed to bringing those people to justice."
The police investigation into the illegal rave has three strands; to identify those involved in the organisation of the event; to identify those involved in violent disorder that took place on the night; and to investigate the circumstances of the death of 15-year-old Rio Andrew.
Rio was taken to hospital in the early hours of June 15 after falling ill at the event in the disused Royal Mail sorting office in Cherry Orchard Road.
Rio, from west London, died in hospital the following day.