Acceleration by Graham McNamee

Duncan still has nightmares about the day he failed to save a drowning girl. His guilt overwhelms him and his relationships with his family and friends suffer because of it.

Duncan takes a mind-numbingly boring job at the transit authority lost and found. One day, while poking around the dusty shelves looking for a book to read, he comes across a mysterious journal. The journal belongs to a serial killer wannabe who documents the acceleration of his crimes--torturing small animals, setting fires, to stalking women on the subway.

Duncan feels driven to stop the would-be killer before he strikes, but when he tries to turn in the diary, the overworked police are not interested. Duncan, with the help of his two very different best friends, sets out to find the killer.
Plot and characterization are both handled well and the suspense gradually builds to an exciting climax. Very well-done mystery that will keep readers turning pages.

Don't skip the interview with the author at the end of the book. It will give you a fascinating glimpse into the writing of the novel--and it's funny.

Blackthorn Winter by Kathryn Reiss

During a trial separation, Juliana's mother takes Juliana and her little brother and sister to live in a tiny artist's colony in England. Juliana's mother plans to find some solitude and peace so that she can start painting again and recapture her artistic self. Juliana understands none of this and misses her dad.

Shortly after Juliana arrives in Blackthorn, her mother's school friend, a nosy and obnoxious woman, is murdered. Though a suspect is jailed right away, Juliana is convinced that the real killer is still on the loose and investigates on her own.

Juliana's investigation leads her to make some mysterious connections with her own past. Can she find the real killer before he - or she- strikes again?

Lots of creepy atmosphere and suspense will keep mystery fans turning pages.