Wendy Allen (Jaimi Paige) is a villainess from Rizzoli & Isles' sixth season finale, "A Shot in the Dark" (airdate March 15, 2016). She was a cellmate and lover of Alice Sands, who was revealed in the previous episode, "Bomb Voyage", as an evil and psychotic mastermind who was targeting Jane Rizzoli.
Wendy was serving time for prostitution, but she was released two weeks before Alice was. At the beginning of the episode, Wendy was driven by her female lover to buy provisions at a general store in rural Maine, where the unseen Alice shot and killed (through a car window) a state trooper who identified the car's license plate as a stolen car. A store clerk heard the gunshot but was knocked out with a bottle to the head by Wendy who stole the clerk's gun. Seeing that Alice had driven off, Wendy escaped to a wooded area. Jane and her brother, Frankie, were at the scene after learning about the villainous couple being in the area; during their search, a gunshot was heard — which was later revealed to be Wendy shooting and killing a police dog.
Later on, Wendy approached Jane from behind her and held her at gunpoint, but she was easily talked down by her hostage, who told Wendy of the trouble she would face due to the state trooper being murdered. Wendy was handcuffed and arrested, but Jane's attempts to tell her that Alice had just been using her fell on deaf ears, as Wendy insisted that Alice loved her. She let slip that Alice had a son, but refused to tell Jane who/where he was. After that, she was taken into custody.