Rx Alibi (3rd Book in the Pharmacy Sleuth Trilogy)
by Renee Horowitz
When Andrea Felder is murdered, pharmacist Ruthie Kantor Morris discovers a prescription drug the police have overlooked. Does it pinpoint the killer or is it a false lead? Suspects include Ruthie's best friend, Denise, and the mysterious Tony--Denise's abusive former boyfriend. Ruthie faces a hostage confrontation at the supermarket pharmacy, which leads her to an even more terrifying situation.