Police investigate if U2 gig 'gunman' was officer

Hundreds of fans spent several hours queuing outside the arena in southern Stockholm before being informed that the Irish rock legends would not be appearing on stage. Others who had arrived early and already taken their seats were escorted out of the arena by security guards.

Organisers initially said that technical issues meant that the gig could not go ahead and promised fans that the gig would be rescheduled for Tuesday.

“We apologize for the inconvenience and hope for understanding from fans. Safety is our top priority," said Live Nation in a statement.

But it later emerged that police were investing suspected gun crime at the venue after fans inside the building said they had spotted security guards searching the floor around the stage.

According to Sweden’s Aftonbladet newspaper, the incident began when it became known to guards that a man with a gun had been let into the arena after showing the weapon at the security checks.

The tabloid wrote that the man had been allowed to enter after claiming he was an off-duty police officer and had forgotten to leave his gun at work.

Later on Monday reports emerged in Swedish media suggesting that an officer was facing an internal probe over the incident.

Jan Friberg at the police's internal investigation unit was unable to give a detailed comment but confirmed to The Local that he had received a report which had been handed on to the investigating team.

"It could be that there has been some form of mistake," he told Aftonbladet earlier in the day.