A "watershed moment" has been reached with the killing of a 15-year-old boy in an apparent case of mistaken identity, detectives believe.
Tributes to Jessie have been left near the scene of his shooting
Officers and community leaders have appealed for help in solving the murder of Jessie James, who was gunned down in Moss Side, Manchester at the weekend.
Greater Manchester Police are to review their initial response to the shooting after some criticism from his family.
It is believed Jessie was not a gang member and was just in the wrong place.
The teenager was killed with a semi-automatic pistol in a park on Raby Street in the early hours of Saturday.
A post-mortem examination showed he was killed by three bullets - two to his torso and one to his appendix.
Ch Supt Dave Thompson said: "I ask people to examine their conscience. We have reached a watershed moment in the community with this terrible loss of a life for someone so young.
"We have had great success in the past in working with the community to help solve similar cases and we hope for the same again."
Jessie's mother Barbara Reid claimed in a Sunday newspaper it took nine hours for a police family liaison officer to visit her family.
Addressing her comments, Mr Thompson told the BBC: "I do recognise the points that Mrs Reid has said.
"We didn't meet her needs at this terrible time. As a result we are going to carry out a review of the first 24 hours management of this."
The police chief emphasised there had been positive contact with Jessie's family since and they were a critical part of the inquiry.
Mr Thompson also denied claims Moss Side had a problem with gun crime - and was backed by community leaders.
Erinma Bell, chair of the Community Alliance for the Renewal of the Inner South Manchester Area (Carisma), said the authorities had to look at how guns were getting on to the streets.
But she also said community relations with police had improved in recent years.
"A lot of good work has been done on both sides and we no longer feel isolated," she said.
Jessie lived in Greame Street, Moss Side and attended the nearby Manchester Academy High School, where he was studying for his GCSEs.
His mother, Barbara Reid, 47, a member of a local Seventh Day Adventist church, has said her son was a "lively, bubbly boy who was loved by everyone".
Jessie's killing comes 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 the area.