Dana Powell is the main villainess in Elementary's "When Your Number's Up" from Season Three.
She was played by Alicia Witt, who also portrayed Paula in “The Walking Dead”.
The beginning of the episode showed Dana Powell hocking her ring and then feeding a homeless man nearby, just before she puts on a pair of black gloves and kills him with a silencer. After shooting him, Dana leaves a stack of money inside an envelope on his body. Dana later attends a group meeting and approaches one of its members, before also killing him as well, leaving the same monetary calling card. Police are called to Dana's house after someone shoots through her window in an attempt on her life. Footprints are found at the front of the house, but as Sherlock Holmes discovers, they belonged to Dana's husband, who was killed in a plane crash. It was also revealed that Dana's victims also lost loved ones on that same flight, and she was the one who shot her own window and made the prints. Before Dana was taken in, she clutched a knife and was appearing to be in the beginning process of killing her own sister, who was questioning her. As for Dana's motive, it was solely for money. Her husband was quite rich and she wanted to remain in the lavish lifestyle she had. The airline responsible for the crash was paying monetary settlements to the relatives of the victims, but Dana was hoping for a larger lump sum, hence her reason for her murderous spree.
- “When Your Number's Up” was the first episode of Elementary to reveal the killer in the beginning of the episode. CBS heavily promoted the "whydunnit" episode, obviously without revealing Dana Powell as the antagonist.