Death Note: Another Note (The LA BB Murder Case)

Hardcover Prequel of Death Note. Story is of L trying to solve a string of serial killings by BB in Los Angeles. The book is in near mint condition. I read it once about 10 years ago and it was in storage since. The white paper cover has some discoloration that appears to be dirt but I'm not sure. It wasn't there when I put it in the storage tote with my other Manga so I'm not sure where it came from but I'm sure it'd be easy to remove.