Eleven police officers are being investigated over the handling of a car crash in July 2023 that killed two schoolgirls.
As well as questions over the standard of the investigation and whether officers provided false information to those affected, the IOPC is also looking into whether officers' treatment of the families was influenced by their race.
The Independent Office for Police Conduct (IOPC) said a former detective inspector and four serving officers - a commander, a detective chief inspector, a detective sergeant and a detective constable - are all being investigated for possible gross misconduct.
Nuria Sajjad and Selena Lau, both eight years old, died when a "distinctive gold" Land Rover driven by Claire Freemantle crashed into an end-of-term tea party on the lawn of The Study Preparatory School.
More than a dozen people were also injured.
Ms Freemantle was not charged for the incident after it was announced she had suffered an undiagnosed epileptic seizure behind the wheel.
"On the 6th of July 2023, our lives were irreparably shattered by a cruel tragedy," said the families of Nuria and Selena in a statement.
"The past 33 months have been incredibly difficult for everyone affected, including those who lost family, were seriously injured or witnessed the horrific incident, and we are still trying to come to terms with what happened on that fateful day."
They said they were "encouraged" that the IOPC had opened an inquiry, adding they have "always sought the truth" around the events of "that devastating day and subsequent actions taken by the Metropolitan Police".
"We have always maintained that the initial investigation was flawed. When the Crown Prosecution Service took the decision for no further action against the driver on the 26th of June 2024, we asserted that the original investigation was poor, and we were unconvinced that the investigation was conducted thoroughly.
"The truth must come to light," said the families.
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IOPC director Amanda Rowe said the police watchdog's "thoughts are with the families and friends of Nuria Sajjad and Selena Lau and all those who were affected by the tragic incident".
"We are investigating complaints made against 11 Met Police officers over their handling of the initial investigation into the road traffic incident."
"The complaints relate to concerns about the standard of the investigation, including its management and direction, the conduct of the investigation team, and their engagement with the victims," said Ms Rowe.
"We are also investigating allegations that Met officers provided false and misleading information to those affected and whether the officers' treatment of those affected was influenced by their race."
She said that as part of the investigation, IOPC investigators have met with the complainants.
The Met police said in 2024 it was reopening its investigation into the crash and rearrested Ms Freemantle in 2025.
After the IOPC's announcement, it said officers had submitted a full file of evidence to the CPS on 17 March 2026 that prosecutors were continuing to consider.
"Our thoughts remain with Nuria and Selena's families, as well as everyone who has been impacted by this terrible tragedy. We understand this prolonged process has compounded their grief and suffering," said Commander Charmain Brenyah, who leads the Met's Roads and Transport Policing Command.
"It is right that our initial handling of this incident be independently scrutinised, and we will provide every assistance to the IOPC as their investigation continues."
The Crown Prosecution Service (CPS) said there are "some further factors we must consider before a decision on charge can be reached".
"We appreciate the ongoing distress any delay may cause and are committed to making a final decision as soon as possible," said a CPS spokesperson.
(c) Sky News 2026: Police officers investigated over race allegations after two girls killed in Wimbledon car crash<
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