Cold To The Touch by Cari Hunter

Winter in the Derbyshire Peaks: months of knee-deep snow, short days, and rocketing crime rates.

Detective Sanne Jensen is living in self-imposed isolation and quietly falling apart, while Dr. Meg Fielding--Sanne's best friend and occasional lover--is struggling to cope with her violent brother, who is back in town and demanding money that she doesn't have.

When the murder of a drug addict is dumped onto Sanne's already unmanageable caseload, she suspects the death may be the start of something more sinister. But how can she investigate a crime when no one cares about the victim? And how can she stop a killer who has no identity, no motive, and no conscience?