An unsolved brutal murder in a busy nightclub has raised further fears about a deterioration in public safety in Tokyo's Roppongi district, where the number of reported assaults has more than doubled in the past nine years. Three weeks have passed since a 31-year-old man was beaten to death by nine masked men at a Roppongi club, but the assailants remain unidentified and at large.

At about 2:40 a.m. on Sept. 2, two vans stopped in front of a multitenant building about 200 meters from the main Roppongi intersection. An hour later, nine men wearing sweatsuits and carrying metal bats got out of the vans and headed to "Flower," a club on the second floor of the building. They put on full-face ski masks as they neared the club.

Being a weekend night, "Flower" was crowded with more than 200 people. The masked men walked straight to a VIP area at the back of the club where Ryosuke Fujimoto was drinking with friends and started bashing him with their bats. Without uttering a word, they continued their deadly assault for about a minute before making their escape.

Based on security camera footage and other information, the Metropolitan Police Department has found that the vans took the metropolitan expressway toward Higashi-Yamato, western Tokyo.

Police suspect the attackers are a group of men in their 20s and 30s with gang ties.