Streatham terror attacker Sudesh Amman had been living in a nearby bail hostel for less than two weeks after his early release from prison.
The manager of the hostel on Leigham Court Road said he had last seen the convicted terrorist on Friday, adding: "He didn't speak much."
He spoke as police continued to search the three-storey building - and neighbours spoke of their concern that "people like that" are living so close.
The hostel manager, who did not want to be named, said:
The manager said hostel residents would sometimes socialise together by playing pool or watching TV.
When asked how long Amman had lived there, the manager said: "I think about under two weeks he had been there."
Amman, 20, who had recently been released from prison after serving half his three year and four month sentence for possessing and distributing terrorist documents, was shot dead by police after launching his terror attack in Streatham High Road on Sunday.
Andrei Marius, 40, who lives opposite the building, said:
Fatima Amaral, 62, who also lives nearby, added: