Ms Nessa had been walking to meet a friend at a pub near her home when she was attacked in a park in Kidbrooke near Greenwich on September 17. Her body was discovered by a member of the public the next day, having been hidden under a pile of leaves, it was reported.
The Metropolitan Police said this morning they arrested a 38-year-old man on suspicion of murder in what Scotland Yard said was a "significant development".
Detective Chief Inspector Neil John, from the Met's Specialist Crime Command, said: "Sabina's family have been informed of this significant development and they continue to be supported by specialist officers."
This is a breaking news story. More to follow.