The Mysterious Murders
One by one, the mane 6 are killed in their sleep. Eventually, when there is only two ponies left, Rainbow Dash has to know who's killing them.
One morning, Fluttershy is discovered to be dead. More specifically murdered! The next day, another pony's gone, and then another. Rainbow Dash has to find out who's killing them before she gets killed herself.
Third Person Story about Rainbow Dash
The first story that I actually put some form of effort into to make the cover art. 
4541 words: Estimated 23 minutes to read
Download:
6 Chapters:
- Day 1 2013-02-13 04:55:18 UTC1015
- Day 2 2013-02-15 05:38:51 UTC837
- Day 3 2013-02-15 23:46:20 UTC907
- Day 4 2013-02-16 03:38:26 UTC588
- The Last Night 2013-02-16 03:49:05 UTC1059
- Twilight's Epilogue 2013-02-19 04:34:49 UTC135