Garnethill by Denise Mina.
Review:
Maureen wakes up one morning after a night of drinking to find her ex-boyfriend murdered in her apartment. Maureen is a suspect in the case and finds it hard to shake that role when her past involves a psychiatric hospital stay. Many think she's crazy and has poor memory. Maureen knows different and takes matters into her own hands as she sets off on a hunt for the killer.
