The police watchdog is investigating complaints made against 11 officers over their handling of an inquiry into a car crash that killed two schoolgirls.

The Independent Office for Police Conduct (IOPC) has confirmed that the officers, including a serving commander and a detective inspector, are being investigated over alleged gross misconduct.

Nuria Sajjad and Selena Lau, both eight, died in the incident at the Study preparatory school in Wimbledon, south-west London, in July 2023 during a tea party to celebrate the last day of the summer term.

As part of the investigation, the IOPC is examining allegations that the race of the victims’ families influenced the conduct of the officers, and whether the families were given false and misleading information.

Claire Freemantle, the driver of a Land Rover that crashed into the school, was not charged as the Crown Prosecution Service said she had had an undiagnosed epileptic seizure. She said she had no recollection of the incident.

She was rearrested and released under investigation in January last year. The Met submitted a full file of evidence to the CPS on 17 March after it reopened the investigation in October 2024.

The girls’ families, who have previously said they were unconvinced that the initial investigation had been carried out thoroughly, welcomed the IOPC’s inquiry.

In a statement, the IOPC’s director, Amanda Rowe, said the watchdog began investigating the 11 officers over their handling of the initial inquiry in August last year. She said it followed a “referral from the Met police of complaints made on behalf of individuals who were affected by the incident”.

Rowe added: “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.

“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.”

Four serving officers – a commander, a detective chief inspector, a detective sergeant and a detective constable – and one former detective inspector are being investigated for alleged gross misconduct.

Rowe said two serving detective constables were being investigated for alleged misconduct. All those being investigated have been served notices and are due to be interviewed.

Rowe added: “The serving of notices does not mean that proceedings will necessarily follow.”

A statement from the families of Nuria and Selena said: “On 6 July 2023 our lives were irreparably shattered by a cruel tragedy. 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.

“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 26 June 2024, we asserted that the original investigation was poor, and we were unconvinced that the investigation was conducted thoroughly.

“We are encouraged that the Independent Office for Police Conduct have opened an inquiry. We have always sought the truth and will continue to champion the pursuit of complete clarity on the events of that devastating day and subsequent actions taken by the Metropolitan police. The truth must come to light.”

Nuria’s mother, Smera Chohan, told the BBC, which first reported the investigation: “I really want to understand why I have been treated so cruelly, unfairly and in an inhumane way. I would like the keepers of law, of the system, to come and tell me.”

Chohan, who was seriously injured in the crash, added: “I am not asking for any favouritism, any leeway or any sympathy. I’m just saying ‘do it right’.”

Nuria’s father, Sajjad Butt, said: “We are deeply concerned – the CPS has left us in the dark. As the organisation that is supposed to move towards justice for victims, it seems rather unwilling to engage with victims.”