CSI: Crime Scene Investigation: Season 5, Episode 22

5 - 22:

After an exhaustive day, Catherine stops by a bar where she is chatted up by another customer. As she is leaving, he gives her his number on the bar's match box and lashes out when she doesn't want to kiss him. Later on that night, Grissom calls in for a favor as he is short on staff. A woman was murdered. Prior to her death, she was seen with the same man who was hitting on Catherine in the same bar. A similar match box with a phone number inside, found on the victim, further points to this man as the main suspect.