Footage of Manchester Arena bomber Salman Abedi watching music fans arrive for a Take That gig days before his attack has been shown to a jury.
Abedi can be seen looking at box office queues, just yards from the spot where, four days later, on 22 May 2017, he killed himself and 22 others.
Hashem Abedi, 22, is on trial at the Old Bailey, accused of helping his brother plan the attack.
He denies 22 murders, attempted murder, and conspiring to cause explosions.
The attempted murder charge encompasses the scores of people who survived the attack, which happened at the end of an Ariana Grande concert.
The jury was shown CCTV footage in which Salman Abedi travels to the Arena venue, spending more than a minute in the City Rooms section where crowds can be seen milling around him.
He then leaves for the nearby Arndale shopping centre, where he buys four nine-volt batteries and a large blue Kangol suitcase, used to transport his bomb-making equipment to his Manchester city centre flat.
Earlier he was seen leaving the flat in Granby Row at about 18:00 BST.
The hooded figure, wearing jogging bottoms and white trainers, was seen moving through rush-hour traffic.
Abedi, then aged 22, also swaps his Sim card between phones and takes an untraced international call during the visit, where he walks the perimeter of the Arena venue before going inside to the City Rooms.
Jurors heard he took the suitcase to Devell House, a block of flats in Rusholme, south Manchester, the next day.
The prosecution said that on 14 April, the Abedi brothers left a Nissan Micra outside the flat and that the vehicle had been used to store bomb-making chemicals and equipment until Salman Abedi returned from Libya to carry out the final stage of the plan.
Salman Abedi loads the suitcase and is seen struggling to drag it up the steps at his city centre apartment, where the prosecution allege he assembled his device.
Jurors were also shown CCTV footage allegedly showing Salman Abedi taking a taxi to a B&Q store in Cheetham Hill where he spent nearly £200 on items including 4,000 screws, metal nuts, a swing bin, a spade, a saw, glue, tape, a set of drawers and an oak effect door.
Store worker Steven Dooley told police he woke on 23 May to see the "devastating events" of the previous evening on the news.
Mr Dooley said that, two days before the Arena bombing, he remembered seeing a young man "acting suspiciously".
"My attention was drawn to him mainly because he had his hoodie over his head and I thought he might be shoplifting," he added.
The jury was also taken through Salman Abedi's phone records from the afternoon of the bombing, which included multiple calls to an unknown Libyan number.
The identity of the recipient has never been established.
Hashem Abedi insists he is not an extremist and had no idea of his older brother's plans.
The trial continues.