Salman Abedi was able to hide in CCTV blackspots in the foyer of Manchester Arena for nearly an hour prior to the attack on the audience leaving an Ariana Grande concert in 2017.
A report due to be published on Thursday into the Manchester Arena terror attack which killed 22 people and injured hundreds more is likely to find widespread failings in the security of the venue.
Abedi detonated a bomb in May 2017 at the end of the US singer's concert.
Figen Murray, whose son Martyn Hett, 29, was one of the 22 people murdered, said she was "anxious" ahead of the publication.
She has been campaigning for Martyn's Law to make venues have action plans against such attacks.
At present it is up to venues to decide whether or not to adopt recommended security measures.
"I am slightly anxious to see what today brings in terms of the first report," she said on Twitter.
"Looking forward to hearing all the recommendations. So hope #martynslaw will be part of it as we worked so hard on this."
An inquiry has been examining the circumstances surrounding the suicide bombing.
It is due to publish its first report into the security arrangements at the venue.
It is expected to focus on how Abedi was able to hide in CCTV blackspots in the foyer of the Arena for nearly an hour prior to the attack.
During the inquiry, the emergency services have also been criticised for their slow response, and bereaved relatives and survivors have condemned delays in the treatment and evacuation of victims.
The Manchester Arena Inquiry is examining the circumstances of the attack and whether any opportunities to prevent it were missed.
The report is expected to look at British Transport Police, who were responsible for keeping people safe in the area on the night, and Arena operator SMG and its contracted event security provider Showsec.
SMG, Showsec and British Transport Police have already accepted shortcomings in their risk assessments.
The inquiry was established by UK Home Secretary Priti Patel last year.
Suicide bomber Abedi, 22, died after detonating a rucksack bomb in a foyer of the arena.
His younger brother, Hashem Abedi, was convicted last year on 22 counts of murder, one count of attempted murder and one count of conspiracy to cause an explosion.
He was sentenced to jail for a minimum of 55 years.
