Macau police raided casinos and hotels in an effort to prevent gambling-related crimes taking a hold over the region once again, Asahi Shimbun reports.

The world’s largest gambling destination became the stage for gang wars in the late 1990s. Triad boss, “Broken Tooth” Wan Kuok-koi, notorious at that time, will be released from jail in the coming months. A recent spate of murders – including attacks on a prominent business figure and two separate murders of three Chinese women – prompted the police to round up about 1,300 people while 150 people were detained for questioning under the operation codenamed “Thunderbolt”. A Macau police spokeswoman told Reuters that, “This operation is an annual exercise to maintain public security” in Chinese territory.

According to the Financial Times, Macau’s gambling revenues saw a monthly double-digit growth over the past years, but the tighter credit conditions slowed it down. Analysts also blame the increased pressure from so-called “Chinese junket” operators for the crimes.

More at the FT.