Stone Cold
Robert B. Parker
 A couple of middle-aged thrill killers, Brianna and Anthony Lincoln, are independently wealthy from a patent Anthony obtained for an optical scanner he invented while practicing medicine. The couple move to Paradise and begin picking random people and murdering them by simultaneously shooting them in the heart with .22 caliber pistols. They then make love while watching videos of the murders. Kenneth Eisley is the first victim; Jesse does not discover his identity until after some investigation, and finds his dog. The Lincolns then stalk and kill a woman in a supermarket, and Jesse has the license plate numbers collected from all cars present at the scene. Next the Lincolns murder a man behind a church as he walks home from the train station. Two teenage boys stumble on the body while skateboarding and notice a red 1995 Saab. With the help of the state police, Jesse finds all people who have both registered .22s and a red 1995 Saab, and checks if there was a red Saab at the supermarket. This leads Jesse to the Lincolns. Jesse briefly interviews the Lincolns, who seem very interested in the murders. He takes their .22 rifle for testing, but it has never been fired. However, he leaves convinced they are the killers. The murderers then stalk Abby Taylor. Although Abby is considering marrying another man, she still has feelings for Jesse. After spending an evening with Jesse and making love to him, she returns home and is murdered by the Lincolns. They begin stalking and taking photos of Jesse, who learns of this while tailing them one night when they stop at his condo to take photos. Flirting with getting caught, and hoping to prove how smart they are —and how dumb the police are— the Lincolns invite Jesse to lunch. They probe him about the murders, but he reveals little. Later, a note is delivered to the police station telling Jesse to come to Paradise Mall at 7pm to learn about the murders. Believing they intend to murder him, Jesse stations officers at the mall and goes wearing a bullet-proof vest. As he approaches the elevator in the food court he is confronted by the Lincolns as they exit it, and they both shoot him in the chest and re-enter the elevator. Jesse bounds up the escalator, but the elevator descends again. When they exit, they have changed clothes. Officer Anthony D’Angelo thinks he recognizes the woman and stops her; she turns and shoots him in the head, killing him instantly. They escape in a rented Volvo. Feeling guilty for D’Angelo’s murder, which he believes could have been prevented had he involved the state police, Jesse trudges on with the case. He took it personally after Abby’s murder, and wanted to catch the killers without the state police. They obtain a search warrant for the Lincolns' rented penthouse condo and find pictures of the victims on their computer, and the abandoned Saab. Jesse’s ex-wife Jenn wonders how they got to the mall without their car, which leads Jesse to check car rentals and match them with names of people who patented optical scanners. One was rented on the day of the murder to Arlington Larmont: Anthony Lincoln was an alias. Jesse discovers that the car was dropped off in Toronto, and the state police find the couple registered at a Toronto hotel, where they are picked up by local police. Jesse drives up to confront the couple, who play dumb. Jesse responds by kneeing Arlington in the groin. When his wife jumps up to defend her husband, Jesse slaps her, then leaves.