From the NY Times:
Clad in black and speaking Chinese, the three men entered a mah-jongg parlor hidden in a building on Hester Street in Chinatown. They pulled out a pistol and a knife and stripped gamblers of more than $5,600, the police said.
A newspaper article about a police raid was posted in the entrance of a building in Flushing, Queens, where a gambling parlor was recently robbed.
Over the next seven weeks, from late February to early April, three more parlors were robbed: one in Chinatown and two in Flushing, Queens. Each was hit by a small group of Chinese-speaking men with firearms — in one case, an assault rifle.
The robbers may have counted on the silence that has long kept these places in the shadows: The gambling is illegal, so owners and bettors are unlikely to report crimes. But in these cases, victims did, opening a peephole into the busy world of underground Chinese gambling and rattling many of those who work and play in it.
Several gamblers in Flushing said two more parlors were robbed this month, though the attacks were not reported to the police. “We’re really scared now,” one player said as he emerged from a secret den. “Now we have to be especially careful.”
The parlors are tucked in basements or upstairs in warrenlike office buildings, places where a steady stream of players can go unnoticed in the commotion of everyday traffic, say gamblers and others in the Chinese community. Some games take place in private apartments, with paper covering the windows or shades pulled tight, or in the backrooms of community associations.
Because operators frequently shift locations to avoid police detection, it is unclear — to the authorities as well as to those who work there — how many parlors there are.
But the police, familiar with the business for generations, said they were surprised by the sudden rash of armed invasions.