it's possible that the episode you're thinking of is "The Case of the Murdered Actress (Part 1)" from Detective Conan (Case Closed) episode 250.
In this episode, the victim is an actress who is found dead on the parking lot below her balcony. At first, it seems like a suicide, but Conan later discovers that it was actually murder. The murderer turns out to be her lover, who had snuck into her apartment and strangled her to death, and then threw her body off the balcony to make it look like suicide.