If She Ran: A PI Thriller (Martina Monroe Book 2) by H.K. Christie - Kindle Edition

Standalone, but book 1 was posted earlier this year. Hopefully you got it.

Three months. Three missing women. One PI determined to discover the truth.

Back from break, PI Martina Monroe clears the air with her boss at Drakos Security & Investigations and is ready to jump right into solving cold cases for the CoCo County Sheriff’s Department.

Diving into the cold case files Martina stumbles upon a pattern of missing young women, all of whom were deemed runaways, and the files froze with minimal detective work from the original investigators. The more Martina digs into the women’s last days the more shocking discoveries she makes.

Soon, Martina and Detective Hirsch not only uncover additional missing women but when their star witness turns up dead, they must rush to the next before it’s too late.