It's Criminal Intent. It's part of the ongoing series of Goren vs his nemisis Nicole Wallace(Olivia D'abo). The episodes where they butt heads rock.

They actually figured she was a messenger because she knew the streets and where things were really well. The original airing of this episode had multiple endings and there was an on-line poll to determine whether Nicole lived or died at the end. 'Living' won,and D'abo came back in at least one more episode. There really wasn't any real bike content in this episode;the girl was on a bike for like 3 seconds and it wasn't critical to the plot. Still a good watch though.

Yeah,I'm kinda a Law & Order junky.