From the Consular Information Sheet on Japan:

Concerns Regarding Roppongi, Tokyo: We note that an American Citizen was murdered in early December 2004 in the Roppongi district of Tokyo. The murder occurred in an office building within walking distance of the local police station. A second foreigner (not an American) was stabbed to death in Roppongi in January 2005. We previously advised Americans of six reports of western foreigners (including Americans) allegedly overdosing on heroin, resulting in three deaths. The heroin was allegedly purchased in Roppongi. We note that several Americans reported the theft of their purses and wallets, stolen from them while in bars and clubs in Roppongi. A number of Americans have also been arrested over the past year in Roppongi for various offenses. Americans are strongly advised to exercise caution should they choose to visit the Roppongi area.

Guess where we spend most of our time in Toyko? Yes, it’s seedy. Yes, the beer is overpriced. But, it’s about the only place in Tokyo where you can get a good hamburger.

UPDATE: I got some more information from the newsletter of the U.S. Embassy in Toyko:

According to information assembled through a variety of sources, including the media, US military reporting and the Azabu Police Station in Tokyo, around 0400 on January 3, 2005, a foreigner was stabbed to death at a club called “Wall Street House,” also known as “Wall Street II,” at Roppongi 5-chome, Minato-ku, Tokyo. The victim’s passport showed he is 26 years old, and from Uruguay. However, there is a possibility that the passport was fake.

No Americans were involved, though Americans have been known to frequent the club. At least one American has reported that his passport was stolen from him in this same club in the past. There appears to have been no relationship between this murder and the December 2, 2004 murder of an American Citizen nearby at Roppongi 7-chome.

I’ve been to the Wall Street, and on most nights, it gets packed. In a space no larger than my living room, they can have 100 people in there.

Also, for those of you unfamiliar with Tokyo society, murders are extremely rare, even in such a large city. A single murder is noteworthy, and worth an embassy warning.