Six people were held in the aftermath of the attack, with two – a man and a woman – arrested in the hours afterwards and then released on Sunday evening.
The following day, detectives said they had been given extra time to question the remaining four, who were also detained on “suspicion of commission, preparation and instigation of acts of terrorism”.
On Wednesday, Greater Manchester Police said they too were set to be released but that “did not mean the investigation was complete”.
Also on Wednesday, the force revealed Al-Shamie made a 999 call in which he pledged allegiance to the group calling itself Islamic State.
Melvin Cravitz, 66, and 53-year-old Adrian Daulby died in the attack on Middleton Road in Crumpsall.
Mr Daulby suffered a gunshot wound after armed police officers responded to the incident and shot Al-Shamie dead.
A police bullet also struck another man, Yoni Finlay, who is recovering in hospital after surgery.