A boy who murdered 11-year-old fellow pupil Joe Geeling has apologised for his actions.
Joe Geeling suffered from cystic fibrosis
Joe was stabbed and beaten to death by Michael Hamer after he lured him to his house in Bury, Greater Manchester, in March 2006.
The Bury Safeguarding Children Board (BSCB) report found the authorities could not have prevented the killing.
Hester Ormiston, who conducted the review, said he had been asked by Hamer and his mother to express deep regret.
Hamer, who was 14 at the time, was jailed for a minimum of 12 years, which was later increased to 15 years at the Court of Appeal.
Joe's parents and Hamer's family were invited to contribute to the inquiry, carried out by a panel of child experts.
The inquiry, commissioned after a serious case review by Bury Council, is required by law to consider the circumstances of all children who die unexpectedly in the borough.
Hamer's minimum term was set at 15 years
The report, published on Wednesday, stated one of the key issues for Hamer was bullying.
His lack of relationship with his father, the death of his half brother in February 2002 and an incident when his wrist was trapped in a door at school were also to blame, the report found.
One issue the report noted was the sharing of information: "While it is not feasible for agencies to share information on every child, when decisions are made about referrals to specialist services the referring agency should gather relevant information from other agencies to provide a more holistic view of the child's life," it said.
"It may be that child B (Hamer) would have had more opportunities to identify his concerns if this had been in place."
Hamer, now 15, is now serving his sentence in a secure local authority unit for troubled youngsters, receiving extensive treatment in the hope of rehabilitation.
He beat Joe Geeling 16 times with a frying pan and stabbed him before dumping his body in a local park.