Manchester suicide attacker Salman Abedi bought most of the components used to make the bomb himself, police have said.
Many of the bomber’s movements and actions were “carriedout alone” in the four days prior to the attack, Russ Jackson, head of the North West counter terrorism unit, said.
But police have yet to rule out whether he was part of a wider network.
Three men arrested over the attack were released without charge on Tuesday.
Det Ch Supt Jackson said much of the police investigation had been working through Abedi’s last movements.
Officers have examined his movements on CCTV and other interactions he had with people as well as phone calls he made.