Amateur City (A Kate Delafield Mystery Book 1) by Katherine V. Forrest

LAPD Detective Kate Delafield is investigating a murder in a high-rise office building when she meets Ellen O’Neil, the crime’s only witness. What begins as a routine investigation becomes increasingly complicated as Kate finds herself unexpectedly drawn to Ellen.

While pursuing an unpredictable amateur killer, Kate must balance the dangers of the case with a growing personal connection that threatens her carefully guarded professional boundaries.