The Silent Corner by Dean Koontz (2017) Bantam

Jane Hawk was an FBI agent married to a Full Colonel with a happy life and a son they adored.  Inexplicably one day her husband goes to get something in their bedroom and kills himself.  When she begins to investigate a suspicious rise in unexplained suicides, she gets a threatening phone call.  So she goes underground, first placing her child in the home of a couple who are already off the grid, then she starts hunting these people who are finding a way to control people and convince them to kill themselves.

The Soul Stealer by Alex Archer (2008) Gold Eagle

Annja Creed goes on a potential archeological dig in Siberia. But the local town has to deal with a legendary monster that hunts at night.

Shakespeare's Counselor by Charline Harris (2001) Minotaur Books

Lily Bard is trying to become a licensed private eye and get her psychological problems under control.  But the counselor has problems of her own.

Phantom Prey by John Sandford (2009) G.P. Putnam’s Sons 

Lucas Davenport is coerced into investigating a cold case.  It turns into a serial murder case as a result, leading to a surprise ending.

Red Sparrow by Jason Matthews (2013) Scribner

A ballerina is intentionally injured by a competitor and wreaks her revenge.  Then she is offered a way to keep her mother in their apartment by becoming a spy. She is sent to Sparrow school, where she is trained to seduce foreign diplomats so they can be blackmailed to give up state secrets.

Black Wing by Connie Suttle (2018) SubtleDemon Publishing 

Quin becomes embroiled in intrigue and love.  The Avii commander, the Elf King, her protectors, and those she heals and saves - all want to be her lover.  But foremost in her mind is to find and kill the being who blew-up the world where she was raised.

Keeper by Connie Suttle (2018) SubtleDemon Publishing 

Finder becomes Quin and her wings are like no one else.  She is outcast by a jealous woman to the Avii, other winged folk, who kill half-breeds on sight.  But the Orb seems to know and use her, though she has no idea why.