"We do believe that there are other people potentially involved in this".
Salman Abedi not part of a terror network but others 'aware or complicit, ' police say.
Detective Chief Superintendent Russ Jackson, head of the North West Counter Terrorism Unit (NWCTU) told reporters: "We don't have evidence of a large network".
DC Jackson said authorities want to speak to Salman's brother, Hashem, who is now being held in war-torn Libya and are engaging with authorities there.
Detective Chief Superintendent Russ Jackson, head of the North West Counter Terrorism Unit, said officers were "engaged" with the authorities in the war-torn country, where Salman's brother, Hashem, is now being held.
'This is a live criminal investigation where central to it are 22 murdered people, with grieving families'.
Police have previously revealed they believed Abedi had bought bomb parts just days after arriving in the United Kingdom from Turkey.
Senator Johnson clarifies position on health care bill
And that pesky pre-existing condition exclusion, when companies closed down, and employees had to find new jobs, for less salary. Polls have shown the majority of Americans are actually happy with the Affordable Care Act .
Forensic officers who were working at the arena in the days after the attack laid roses next to name plates at each spot where the 22 victims were killed, Ch Supt Jackson revealed.
Abedi was born in Manchester to Libyan parents. He is believed to have visited Libya shortly before the attack, returning to the United Kingdom on 18 May.
Mr Jackson said police were now clear on Abedi's movements in the run-up to the attack, they knew the make-up of the bomb and where parts were obtained.
Ch Supt Jackson confirmed officers want to interview the bomber's younger brother, Hashem Abedi, who continues to be held by Libyan authorities.
The family fled Libya during Muammar Gaddafi's dictatorship, with the father returning to fight with opposition forces when the uprising began in 2011.
Abedi's older brother, Ismail, was among more than a dozen people held and questioned by police in the United Kingdom before being released without charge.
Calls Abedi made, reportedly to his mother and others, on the night of the attack were another "key line of inquiry", Mr Jackson said, but would not be drawn further.
They said he appeared to have spent "many months" planning the atrocity - but had left no note or video explaining his motivations for the attack.