Manchester Arena suicide bomber Salman Abedi made three scouting trips to the venue before murdering 22 people and injuring hundreds of others, a public inquiry has heard.
CCTV footage of the visits, in the days leading up to the attack in the City Room foyer at the end of an Ariana Grande concert on May 22 2017, was played on Tuesday at the hearing into the attack.
Abedi's first hostile reconnaissance was before a Take That concert on May 18, the day he landed in the UK from Libya where his parents lived.
He was captured on film, wearing dark clothing and trainers, arriving at Victoria tram stop at 6.18pm before he exited and walked around the perimeter of the railway station and adjoining Arena complex.
Abedi, 22, entered the City Room at 6.35pm and walked past a security supervisor before he stood with his hands behind his back and observed people queueing to get in the gig for a minute or so.
Shortly afterwards he returned to the tram stop and departed, Manchester Magistrates' Court was told.
Security experts believe he used this initial reconnaissance to identify entrance and exit routes from the Arena, check CCTV locations and may have noticed a CCTV blind spot on the raised level of the City Room.
Inquiry chairman Sir John Saunders asked Detective Chief Inspector Sam Pickering, who dealt with the sequence of events, whether in hindsight it was clear that Abedi was carrying out reconnaissance when observing the queues.
The Greater Manchester Police officer replied: "It's a busy place with lots of people wandering around... it might be hard to spot."
Abedi returned to the City Room at 6.56pm on May 21 before a show by physicist Professor Brian Cox.
Wearing dark clothing again, with a black baseball cap and hood up, he casually jumped on a wall and sat there for six minutes holding his phone to his ear and occasionally looking around before he returned to the tram platform at 7.12pm.
On the night of the bombing he made another reconnaissance trip as he briefly entered the City Room at 6.34pm and then left and had a brief conversation with two security stewards en route to taking a taxi from Victoria railway station at 6.36pm.
Abedi returned on his fateful final journey at 8.30pm, carrying a large rucksack.
He later headed to the raised mezzanine level of the City Room - out of sight of CCTV cameras - where he waited for nearly an hour before he descended the staircase and detonated the bomb at 10.31pm.