LONDON (AP) - A public inquiry into a mass attack at a 2017 Ariana Grande concert in northwest England concluded Thursday that “serious shortcomings” by venue operators, security staff and police helped a suicide bomber who killed 22 people carry out his “evil intentions.”

Retired judge John Saunders, who is leading the ongoing inquiry, said Salman Abedi should have been identified as a threat by those in charge of security at Manchester Arena “and a disruptive intervention undertaken.”

“Had that occurred, I consider it likely that Salman Abedi would still have detonated his device, but the loss of life and injury is highly likely to have been less,” Saunders said.

Abedi, 22, set off a knapsack bomb in the arena's foyer at the end of the May 22, 2017 concert, as fans - including thousands of children and young people - were leaving the pop star's show. He died in the explosion. His younger brother Hashem Abedi was convicted last year of helping plan and carry out the attack.

Saunders recounted missed opportunities to stop Abedi, citing failures by arena operator SMG, security company Showsec and British Transport Police, the agency responsible for patrolling the area in the city of Manchester.

He said authorities showed a reluctance to believe an attack could happen, even though Britain and other European countries had experienced multiple deadly attacks in the previous months and years.

“I have concluded that there were serious shortcomings in the security provided by those organizations which had responsibility for it, and also failings and mistakes made by some individuals,” Saunders said.

He said one of the biggest missed opportunities came when Christopher Wild, who was waiting to pick up his partner's daughter from the concert, became suspicious when he saw Abedi loitering in a CCTV blind spot on a mezzanine above the arena foyer with a large knapsack. Wild said he raised concerns with a security steward but was “fobbed off.”

The judge said it was “distressing” that “no effective steps were taken” to act on Wild's concerns.

Lawyer Neil Hudgell, who represents the families of two victims, said there had been “an inexcusable catalogue of failings at every level.”

Britain's interior minister, Home Secretary Priti Patel, said the government was considering introducing a measure giving public places a legal duty to take steps to protect against terrorist attacks. The idea has been called “Martyn's Law” after a campaign by the mother of Martyn Hett, who died in the concert attack.

“After this report we are one step closer to ensuring that a difference can be made,” said Hett's mother, Figen Murray. “Now the recommendations have to be acted upon by the government, so that all venues have security and that no other families have to go through what we have.”

Saunders' findings came in the first of three planned reports into the bombing by the inquiry, which has been hearing evidence in Manchester since September. The others will look at the emergency response and whether the attack could have been prevented.