Homicide detectives have said that the six people arrested following from the death of a man and a woman in Stockwell were in their 40s to late 50s.
Five men and a woman are all arrested at the scene on suspicion of murder.
Detective Chief Inspector Richard Leonard is leading the investigation said he currently believes “that many of those caught up in the tragic incident are from South American communities.”
Police were called just after 4pm yesterday (Wednesday, 1 April) to Dorset Road, to concerns for the welfare of a man.
Officers and London Ambulance Service attended and two people were found inside the address with multiple stab injuries.
Despite the best efforts of officers and medics a 59-year-old-man and a 56-year-old woman were later pronounced dead at the scene.
The two deceased were believed to be known to each other and their next of kin have been informed.
While at an early stage of the investigation, police are not currently looking for anyone else in connection with this matter.
DCI Leonard said: “I understand that this is an extremely shocking incident for the residents of this area and the wider community. Please be assured that my team are working very hard to understand the circumstance of this terrible event.
“The investigation is at a very early stage, but we currently believe that many of those caught up in the tragic incident are from South American communities.
“We are appealing directly to those communities in and around the local area for any assistance they can give us and will be working closely with our partners and other agencies to reach potential witnesses.
“If there is anybody with any information that could help our investigation please do get in contact, my officers are standing by to take your call and you will be fully supported.”
Any witnesses, or anyone with information that may assist the investigation, should call police via 101, or the incident room on 020 8721 4622. You can also contact police via Twitter @MetCC. Please quote CAD 4286/01APR.
To remain anonymous, please contact the independent charity Crimestoppers on 0800 555 111 or online at crimestoppers-uk.org.