Macau police said Monday they had arrested 150 people during raids on casinos and hotels after a spate of murders raised fears of a return to the gaming hub's violent past.
Police questioned nearly 1,300 people and detained 150 in an operation codenamed "Thunderbolt 2012" conducted across the semi-autonomous Chinese city late Friday, police spokesman Chong Su-pong said.
The operation came after three unsolved murders and an attack on a casino hotel boss, which revived memories of the former Portuguese colony's past troubles with gang-related crime.
Triads, Chinese criminal gangs, were common in the late 1990s, but the only city in China where casinos are legal has cleaned up its image since the gaming sector was opened to foreign competition in 2002.
"The operation was a joint operation among the Macau, Hong Kong and Chinese police," Chong said, adding that a suspect in a Hong Kong murder case was among those in custody.
The raids came after a gang of six people armed with hammers reportedly assaulted Ng Man-sun, a major investor at the Greek Mythology Casino, a firm owned by gaming tycoon Stanley Ho's SJM Holdings, in late June.
The market trader-turned-casino boss remains in hospital.
That assault was followed by the murder of a mainland Chinese woman at a residential area near a casino, and the killing of two Chinese men at a five-star hotel.
Macau's gambling revenues have raced past those of Las Vegas to make the city the casino capital of the world.
But revenue growth has dropped dramatically in the past 12 months in line with a slowdown in economic growth in mainland China, the source of the vast majority of Macau's wealthy VIP gamblers.
Gaming revenues rose 1.5 percent year-on-year in July to 24.58 billion patacas ($3.08 billion), the slowest pace of growth since 2009.
Macau raked in a record 267.87 billion patacas in gaming revenue last year.© ANP/AFP