Case Closed (1996)

Season 12

Episode 13: Mystery of the Birthday Wine

Mouri, Ran, and Conan are invited by Ran's friend to attend their small birthday party. There, a woman is poisoned from drinking wine, but her wine was given after someone else took a drink already. Conan figures out the trick and proves the culprit to be the murderer. The culprit reveals that the victim was his girlfriend who kept on buying expensive items leaving him in debt.