During the event at The Puffing Billy in Smethwick, Birmingham - involving a notorious DJ - 15-year-old Jamar Walker was stabbed near the pub, and later died from his injuries.
Gang crime
At a previous event involving the DJ, a dog walker told police they heard a mention of a gun when passing by the venue.
West Midlands Police concluded performances “attract attendees at his DJ events who are associated to gun and gang crime”.
In past the DJ's events had needed to be risk assessed and well policed due to the perceived threat associated with performances.
Weapons
Police concluded in a report the event which coincided with the murder went ahead “despite being advised of the risk has continued with an event which [the manager] knew would attract persons from the gang fraternity who could be armed with weapons”.
On a separate occasion in December police witnessed “an individual in full view rolling a cannabis cigarette with a number of deal bags containing cannabis in front of him”.
Responsibility
Partner at licensing law firm Poppleston Allen Jonathan Smith urged licensees to take note of the incident.
“All premises licence holders and DPSs owe a duty to uphold the licensing objectives - both protecting children from harm and the prevention of crime and disorder,” he said.
Arrests have been made as detectives continue to investigate the murder of the Smethwick teenager. The 15-year-old was found with stab wounds on Raglan Road, the same road as the Puffing Billy, at around 2.20am on 20 December.
Police appeal
Detectives are now renewing their appeal for information and are asking people who were in and around The Puffing Billy pub, Raglan Road, on the night of Sunday 20 December to come forward.
Inspector Justin Spanner, from force CID, said: "It was just before Christmas and the pub was holding an event, witnesses have indicated that there were a number of people within the area that haven’t come forward.
"We really need everyone who was there to come forward, they may have seen something that they feel is insignificant but they may unknowingly hold vital information.
"I understand that people may feel hesitant in coming forward, I would like to assure those people that we will deal with them discreetly and confidentially.
"The family of Jamar are obviously devastated at the loss of their loved one who lost his life in such tragic circumstances and at such a young age.
“I am appealing to people in the area to think of Jamar’s family and come forward."
Anyone with information is urged to call West Midlands Police on 101. Alternatively people can leave information anonymously by calling Crimestoppers the independent charity on 0800 555 111.