Just what the title says -- mystery stories coming from world history. There are 5 chapters with different themes (assassination, people disappearing, etc.) with about 10 stories in each chapter. The stories are self-contained and no more than 3-5 pages long, which makes it easy to read a whole story in one sitting.
I'll add a little bit of introduction, too. :) My name is Maggie, I'm 23, and I've studied Japanese for about 10 years, 7 of those in the classroom. I took JLPT1kyuu last month so I'm around that level.
Also wanted to let you guys know about this site:
It is the Gutenberg project of Japanese literature. There you can find a ton of reading material and read it straight from the web. I recommend 宮沢賢治, particularly 注文の多い料理店.