The missile smashed on to the roof of the bikers' heavily fortified Copenhagen headquarters at about 3am local time yesterday, injuring 15 people, some seriously, as 150 guests enjoyed their annual "Viking" party.
Suspicion immediately fell on the Hell's Angels' bitter rivals, the Bandidos. This gang, based in Texas, and the Angels, whose world HQ is in California, have been involved in a deadly feud in the Nordic countries for more than two years.
Police believe the fight is over drugs and criminal markets but, whatever the cause, it has now claimed nine lives and 45 people have been injured across Denmark, Sweden, Finland and Norway.
The battles have increasingly moved from the countryside into the towns, and took a sinister twist following a recent raid on a Swedish army depot. Since then there have been three grenade attacks on Hell's Angels clubhouses in Sweden, leading up to yesterday's fatal attack.
One of the victims was thought to have been 29-year-old Janne Krohn, a woman with no known connections with the gang, who was at the party because the Angels wanted to improve their image by opening the event up to neighbours.
"We don't know precisely why she joined the party. She may have reacted to the posters," said police commissioner Ove Dahl. The other person killed was 39-year-old Louis Linde Nielsen, whom police said was being considered for membership of the gang. Among the injured were Hell's Angels' Danish president, Christian Middelboe.
The scene after the blast, in which many injuries were caused by flying shrapnel, was chaotic. The stench of burning rubber hung in the air.
"The idiots got us," screamed one biker as he stormed through a crowd that gathered near the compound.
There was swift political condemnation of the outrage. Prime Minister Poul Nyrup Rasmussen said the attack was "abominable".
But the tragedy is unlikely to improve the Danish authorities' relations with the biker gang. In September, Copenhagen's mayor ordered the Hell's Angels evicted from their headquarters, which the gang rents from the city under a law providing low-cost leases to clubs and civic organisations. The gang has refused to leave.
The government is considering taking action against all biker groups and the topic was a major talking point when the Parliament met last week.Reuse content