The teenager was fatally stabbed in her back when two drug dealers, seeking revenge on a rival, attacked her in a case of mistaken identity.
The Thames Clipper river bus was reportedly untied from its mooring in the early hours of Saturday and driven down the Thames for four miles.
Jeremy Menesses, 17, from south London, died after being stabbed in an assault on Market Place at the junction with Oxford Street in central London on August 8.
Three-and-a-half years since her son, JJ, was stabbed to death, Michelle McPhillips remains in agonising limbo as his killing remains unsolved.
The unnamed officer was taken to hospital after being seriously injured as he carried out a stop and search.
Commander Kyle Gordon, the Met Police's lead for firearms, defended the officers who raided the home of Kai Agyepong in Camden, north London, after he was seen playing with a toy gun.
Officers seized £2.3 million of drugs at his flat, the largest seizure of MDMA and crystal meth from a British home.
Dame Cressida Dick's comments come after several incidents that saw violent clashes with police officers in London.
Uran Nabiev was found guilty of manslaughter and assault occasioning actual bodily harm over the incident in Erith, south London.
The Cenotaph and the statue of Winston Churchill have been boarded up ahead of protests in London this weekend.
The monument was taken down from its plinth at West India Quay in the Docklands on Tuesday evening.
Former Home Secretary David Blunkett said while police officers taking the knee was 'commendable' it would leave many feeling 'uneasy'.
London could come out of lockdown quicker than other parts of the country - despite ministers earlier insisting the government would take a 'national approach'.