Officers from the Metropolitan Police have been in King's Lynn to investigate links to a fatal shooting in London's Chinatown.
There are up to 40 Chinese people living in one house
You Yi He, 37, was drinking with friends in the brb bar in Gerrard Street on Tuesday when he was shot twice by a lone gunman. He died later in hospital.
Detectives believe the killer may have travelled from the Norfolk town, which has seen a huge increase in the Chinese population.
In the last nine months the number of Chinese people living in King's Lynn has increased from 300 to nearly 2,000.
Some are living 40 to a house.
Leading Chinese figures in Norfolk have told the BBC they believe that Snakehead gangs - part of the notorious Triad - have been largely responsible for bringing in the economic migrants.
The migrants' paperwork is then taken off them by the gangs.
This makes it almost impossible to deport them as China will not accept them without their papers.
Witnesses described the gunman as of Chinese appearance, aged 20 to 23.
He had long hair with a fringe covering his face and red highlights at the back.