Lot of nine mass market paperback novels in two different series all by Robert W Walker published in the late 90s

"Walker is perfect for Patricia Cornwell fans... " (a quote from inside one of the books)

JESSICA CORAN

Jessica Coran, a doctor and FBI medical examiner, in Washington, DC

• #3 Primal Instinct 1994
  
• #4 Pure Instinct 1995
  
• #5 Darkest Instinct 1996
  
• #6 Extreme Instinct 1998
  
• #7 Blind Instinct 2000
  

LUCAS STONECOAT

Complete Series - Lucas Stonecoat, a police officer, and Meredyth Sanger, a police psychiatrist, in Houston, Texas

• Cutting Edge 1997
  
• Double Edge 1998
  
• Cold Edge 2001
  
• Final Edge 2004