The police handling of the inquiry into the murder of a 15-year-old is to be independently investigated.
Jessie was shot near the youth club he attended
Jessie James was shot dead in Raby Street, Moss Side, on 9 September.
It has emerged that a call was made to an off-duty police officer's mobile about an hour before police received the first 999 call about the shooting.
Police believe it may have been about an incident linked to his killing. It has been reported to the Independent Police Complaints Commission (IPCC).
Chf Supt Dave Thompson, Divisional Commander, said: "GMP has voluntarily referred this matter to the Independent Police Complaints Commission.
"We need to understand exactly what has happened which is why we have referred this matter.
"Throughout this investigation we have been in close contact with the family and they have been made fully aware of this situation."
Tributes to Jessie were left near the scene of his shooting
A post-mortem examination showed Jessie was killed by three bullet wounds - two to his torso and one to his appendix.
Police had said the murder was first reported in a 999 call at about 0240 BST.
Detectives have revealed a call was made an hour earlier to the mobile of an off-duty police officer not based in Moss Side.
Jessie's killing came less than three months after 45-year-old Ernest Gifford was shot at home on the same street.
And last month, three men were shot and wounded in two separate incidents in other parts of Moss Side.