Penitent - The Sylvia Wilcox Series, #7

Years have passed since Sylvia Wilcox mentioned a missing person case to Sergeant Chris Ruiz, but when he's placed in charge of a newly formed cold case task force, the story echoes in his head. The case file is thin, with little evidence or notes to guide the investigation, but a dangerous trek into Wyoming's rugged mountains reveals shocking evidence of a violent demise. The past is never truly dead, but Sylvia Wilcox is working to move forward in life.
She's taken a leave of absence from her private investigation agency-leaving her return date up in the air. She is working to construct a new life when a late-night phone call interrupts her hiatus.