A three-year-old boy and his 11-year-old sister who were found dead with their parents at a flat in west London, had suffered multiple stab injuries and a knife wound to the heart, the Metropolitan Police said.

The deaths of Maja Wlodarczyk, her brother Dawid Wlodarczyk and their mother Monika Wlodarczyk, 35, are being treated as murder, the force added.

The family was found dead along with Monika’s partner Michal Wlodarczyk, 39, at the flat in Staines Road, Bedfont, on June 16, after Maja’s school called police when she had not attended since June 12 and the family had not replied to messages.

Post-mortem examinations have been carried out and the cause of death for Mrs Wlodarczyk was given as multiple sharp force injuries.

The cause of death for Mr Wlodarczyk was given as sharp force injuries to the neck. The force said they are not able to provide further details on his death at this stage.

Officers are not seeking anyone else in connection with the incident, police added.

It is not yet known on what date the family died.

Inquests were opened and adjourned on Tuesday at West London Coroner’s Court.

Detective Chief Inspector Linda Bradley, who is leading the investigation, said: “Specialist detectives continue to investigate the circumstances which led to this tragic incident.

“We are continuing to support family members at this unimaginably difficult time, and we thank the local community for their understanding in recent days whilst we conducted enquiries at the scene.

“The situation remains that we are not currently seeking anybody else in connection with the incident.”

Anyone with information that may assist the investigation is asked to call 101, quoting reference 5135/16Jun, or via the online form at: mipp.police.uk/operation/01MPS23V28-PO1.