Police were first called on Monday, March 17, to reports of an unresponsive woman inside a building at the Aylesbury Estate in Walworth, SE17.
53-year-old Carmenza Trujillo was pronounced dead at the scene.
A post-mortem examination was unable to confirm a cause of death, and an investigation was launched.
A 40-year-old man was arrested on suspicion of murder on Tuesday, April 1, and later released under investigation while enquiries continued.
Months later, at around 7.30am on Sunday, August 24, officers were called to High Road, Tottenham, where another woman was found unresponsive.
The victim, 39-year-old Sheryl Wilkins, was pronounced dead at the scene.
A post-mortem examination again could not establish a cause of death.
On Thursday, September 4, detectives from the Met’s Specialist Crime team arrested the same 40-year-old man on suspicion of murdering Sheryl and re-arrested him on suspicion of murdering Carmenza.
He remains in custody.
Detective Chief Inspector Neil John, who is leading the investigation, said: “My sympathy goes to the family and friends of both victims, who have been updated on this development and continue to be supported by specialist officers.
“No woman should feel unsafe in our city, and we know this news will cause concern across communities. Our investigation is continuing at pace and remains a priority.
“I urge anyone who has information relating to either incident to contact us as soon as possible.”
Police can be contacted on 101, quoting 1721/24AUG. To remain anonymous, call Crimestoppers on 0800 555 111.
