LONDON (AP) — A jury concluded Friday that a terror attack on a busy street in south London last year could have been prevented had the perpetrator been recalled to prison after he bought items that were used in a fake suicide belt.

Sudesh Amman, 20, was shot dead by armed undercover officers after he stole a knife from a hardware shop and randomly stabbed a man and a woman in Streatham on Feb. 2, 2020, before turning to charge at the two armed police officers who gave chase. The victims survived the attack.

After 11 hours of consideration, the jurors at Britain's high court returned a conclusion of lawful killing but said the probation services “missed an opportunity” to send him back to prison.

Over more than three weeks, jurors had heard that police and security officers from the MI5 intelligence agency had been so concerned about Amman two days before the atrocity that they held an emergency meeting to discuss the prospect of returning him to prison following his recent release.

However, HM Prison and Probation Service opted against recalling him, even though undercover officers spotted him buying four small bottles of carbonated soft drink Irn-Bru, kitchen foil and parcel tape two days before the attack — items they rightly feared could be used to make a hoax suicide belt.

Amman was kept under around-the-clock armed surveillance instead.

The senior investigating officer on the Amman case denied suggestions from Amman’s family that police should have intervened and that the undercover operation was a “massive failure.” He said the actions of the Metropolitan Police that day prevented further tragedy.

At the inquest's conclusion, Judge Nicholas Hilliard praised the police for their bravery.

“Amman was prepared to risk his life," he said. “In stark contrast, the Metropolitan Police surveillance teams were prepared to put themselves in harm’s way.”

Amman was said to have plotted to kill Queen Elizabeth II and to have pledged allegiance to the Islamic State group. While in prison, Amman was also said to have revelled in his perceived notoriety as a young terrorist, and was said to have mixed with other high-profile offenders including the brother of Manchester Arena bomber Salman Abedi.

He was automatically released from Belmarsh jail in London on Jan. 23, 2020, halfway through his 40-month sentence for obtaining and distributing material used for terror-related purposes, despite pleas to the prison governor to keep him in custody for longer after a police officer feared an attack would be “when, not if.”