A commuter described today how one of the 7/7 bombers boarded her bus carrying a heavy backpack and looking nervous and sweaty.
Anita Dybek-Echtermeyer was struck by the "bad manners" of an Asian man who got on a crowded number 91 bus at King's Cross station in London on July 7 2005.
He blocked the way with his large pack and knocked against other passengers, the inquest for the 52 victims of the attacks heard.
Ms Dybek-Echtermeyer later realised that the man was suicide bomber Hasib Hussain, 18, who killed 13 people when he blew himself up on a second London bus in Tavistock Square.
She narrowly escaped being caught in the blast herself when she tried to get onto the bus targeted by the teenage terrorist - but it was too full.
Ms Dybek-Echtermeyer, who in 2005 was a PhD student at Queen Mary, University of London, was caught up in the travel chaos on July 7 caused by three earlier bombs on the London Underground.
She abandoned her plans to take the Tube and got on the number 91 bus at Caledonian Road station.
Hussain boarded the bus near King's Cross station with his large rucksack - which was packed with homemade explosives - on his back and its belt fastened around his waist.
Giving evidence via videolink, Ms Dybek-Echtermeyer told the inquest that he looked "nervous and exhausted".
She said: "People were already packed on the bus and someone pinching them all the time with his backpack, that was really bad manners.
"Everyone was in a hurry to work or whatever, and we were already inconvenienced because we couldn't take the Tube."
Describing the rucksack, she added: "It looked very heavy and very properly packed - full, I think around 60 litres.
"It had to be heavy because he had a strap on to carry the whole thing.
"Also, he himself looked very exhausted and he was sweating on his chin, and that was horrible to look at."
Disruption caused by the earlier Tube bombs meant that the number 91 bus terminated early at Euston station and everyone had to get off.
Ms Dybek-Echtermeyer continued her journey on foot, although she tried unsuccessfully to get on a number 30 bus in Tavistock Square.
Moments later the bus blew up behind her, the inquest heard.
She said: "I walked a few steps, maybe 10 metres, and then I felt this huge noise and this blast of air going through. So I turned and I saw the bus going into the air and I just ran."
She later saw a picture of Hussain in a magazine and realised it was the man on the bus.
Paul Rekret, another passenger on the number 91 bus, recalled that a woman in her 20s tapped the bomber on the shoulder and asked him to be careful but he made no reaction.
He told the inquest: "The bus was quite crowded. The man in question was taller than most people.
"He was almost right beside me, and had a very large, very full, quite new backpack, which as he was turning and looking about was bumping a small elderly woman stood beside me."
He added: "At the time I thought he was a lost and anxious tourist, and perhaps a foreigner.
"But I certainly remember that he was behaving very oddly, otherwise I wouldn't have remembered him."
Mr Rekret got off the bus and was continuing his journey to work on foot through Tavistock Square when the bomb went off.
Describing the scene, he said: "The way I recall it is pieces of the roof of the bus floating down to the ground as a piece of paper would, some of which landed right at my feet, and the bus shaking and people sat on the top deck of the bus as if they were in a convertible."
Mr Rekret recalled that the blast was followed by a moment's shocked silence.
Then one onlooker shouted, "it might go again, it might go again," and those in the square rushed to flee the scene in a panic.