Scotland Yard said a post-mortem examination held at Kingston mortuary found a single stab wound on Carole Waugh's body.
Police said further examinations will be made to establish the exact cause of Miss Waugh's death.
More top news
It was the deadliest such attack in a decade.
China has passed a controversial national security law which makes activities deemed subversive or secessionist punishable by imprisonment.
Hotel and tourism markets in the Isle of Wight, Exeter, Norwich, Blackpool and Cornwall will also be quick to recover, according to new rese