Cops also believe Abedi moved alone in the days prior to the attack.
Detective Chief Superintendent Russ Jackson, Head of the North West Counter Terrorism Unit, said: “Our enquiries show Abedi himself made most of the purchases of the core components.
“What is becoming apparent is that many of his movements and actions have been carried out alone during the four days from him landing in the country and committing this awful attack.”
Much of the investigation around last Monday’s attack has been focused on Abedi’s jihadi support network.
Indeed police have made 16 arrests in the week following the suicide bombing, which left 22 dead at Manchester Arena.
Eleven of those arrested remain in custody.
The focus of the investigation has now turned to a blue suitcase Abedi was seen with on CCTV in the days before the attack.
A Bury rubbish tip was yesterday searched by investigators who believe it could contain vital clues.
But detectives added they are still investigating the possibility killer Abedi worked as part of a sophisticated terror cell.
The statement continued: "It is vital that we make sure that he is not part of a wider network and we cannot rule this out yet.
"There remain a number of things that concern us about his behaviour prior to the attack and those of his associates which we need to get to the bottom of."
Fears that “key players” in Abedi’s cell were still at large prompted the Joint Terrorism Analysis Centre to increase the terror threat level to critical last Tuesday — meaning an attack is imminent.
But the threat was ruled to have receded after yesterday’s raids and the recovery of explosives.
Following a meeting of the Government’s Cobra emergency committee on Saturday, Theresa May said the threat level was being reduced.
The PM said: “The public should be clear about what this means. A threat level of severe means an attack is highly likely. The country should remain vigilant.”
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