Warning: The following report contains details that some may find distressing

A bloodstained knife and blanket later forensically linked to a suspected triple killer were reported to police three days before the murders but not recovered until afterwards, the BBC has learned.

They were found by a member of the public in woods at Costessey, near Norwich, close to the home of Bartlomiej Kuczynski, who is thought to have killed his two daughters and sister-in-law, and then himself.

The Independent Office for Police Conduct (IOPC), which investigated the force's contacts with Kuczynski, said it had not been informed about the discovery.

The force confirmed the items were reported to them three days before the killings but said it had not told the IOPC as they were not connected.

The body of Kuczynski, 45, was found at his house on 19 January 2024, along with those of his daughters Jasmin Kuczynska, 12, Natasha Kuczynska, eight, and their aunt Kanticha Sukpengpanao, 36.

All had suffered stab wounds to the neck.

The deaths of the girls and their aunt are being treated as murder while detectives have said they are not treating Kuczynski's death as suspicious.

The IOPC investigation included a 999 call he made from the family home in Allan Bedford Crescent, shortly before 06:00 GMT, hours before the bodies were discovered, in which he warned he "had a knife and had lost the plot".

At that point he was directed to NHS 111 and a police worker has since been reprimanded over their handling of the call.

The IOPC said it only became aware of the discovery of the knife and blanket, which were found alongside empty alcohol bottles, after its investigation ended.

A spokesman said: "Any matters potentially linked to our investigation should have been disclosed, even if only for our awareness."

Norfolk Police said the find was reported on 16 January and the items recovered on 19 January, "after the incident at Allan Bedford Crescent".

It added that at the time the items were found, there was no information linking them to Kuczynski.

The IOPC said the discovery of the knife and blanket would not "have materially changed the outcome of its investigation or its scope".

It is understood the discovery will feature in the inquests into the deaths, which are yet to take place.

No date has been set for these but a pre-inquest review hearing is scheduled for 26 November.

Further details of Kuczynski's behaviour, and his contact with police, in the month leading up to the killings have also emerged.

The BBC has discovered that the engineer had an interaction with officers on 13 December 2023.

It happened after his vehicle was found obstructing a road in Little Fransham, 20 miles (32km) from his home, where he was also spotted pitching a tent.

The following day he was reported missing and police then found him in a street close to the family home.

He was taken to A&E at the Norfolk and Norwich University Hospital over concerns about his mental health and the BBC understands he attended voluntarily.

According to the Norfolk and Suffolk NHS Foundation Trust (NSFT), the local mental health provider, he was assessed at the hospital but by the time a specialist team had arrived, he had discharged himself.

Following the deaths NSFT commissioned an external serious incident review to "ensure any learning is identified and of course work with partners to collaborate with any external investigations".

It can also be revealed that police had a further interaction with Kuczynski on 18 December.

He called them to ask for help retrieving the tent he had left following the earlier contact a few days previously.

Norfolk Police has declined to comment further ahead of the inquests.

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