for fans of CSI series:NY.Can you help me answer this question?

Can I know what flower did the killer (not sure his name) gave the girl ? I remember watching this episode in one the CSI series( i think is CSI:NY, not sure what season is it).The flower has a dark colour.Was the flower a black dahlia? Or an iris? Or another type of flower?

I can't seem to remember this episode...was it the one this week? If it wasn't, what episode was it, I think I need more details