Those Who Kill

Pittsburgh's newest homicide detective Catherine Jensen is haunted by the disappearance of her brother years ago, and her parents have lost interest in finding him. However, Jensen must focus on her new job when a mummified corpse is found at a demolition site. She knows it is more than just an accident or random murder. She enlists the help of academic forensic psychologist Thomas Schaeffer who suggests a serial killer roams the city. When Catherine gets kidnapped by the killer, Schaeffer must think like him in order to solve the case and save her.

Molbeck investigates the murder of a woman found bludgeoned in a dumpster, while Catherine waits for the D.A.'s decision about her actions with the previous case. Meanwhile, Schaeffer gives his statement to the D.A., then resumes investigating Judge Howard Burgess, Catherine's stepfather

While the team continues to investigate the bludgeoning death at the dumpster and the suicide of a suspect, Catherine and Schaeffer must ask Judge Burgess to look at the suspect's sealed documents for clues. They travel to a rural farm where several adopted children, including the suicidal suspect, were raised. Meanwhile, the killer strikes again, killing a woman who had been questioned by the police.

Angela Early, a nurse at an assisted living home, is revealed to be the killer. A suspect in custody states that the victim found underneath the bridge was her son and approached her that night. The team learns Early was raped as a teenager and her parents forced her to keep the baby. Catherine asks Judge Burgess for help, and he points her to the nursing home. Early commits suicide to prevent being taken into custody.

When Thomas decides to stop working on active cases, Catherine starts investigating his past which leads her to an unexpected family history. Catherine takes Thomas to the basement of her step-father's house where her brother wassexually abused. Thomas tells Catherine he believes that her mother has always known about the abuse.

Thomas's suggestion to Catherine about her mother deeply disturbs her. Meanwhile, the team investigates a possible domestic homicide where a mother and her children are killed. They later find the father dead from a gunshot wound, but his time of death occurred before his family's. Thomas suspects the killer hid in the house's crawlspace, and his re-enactment affects his own family, as the killer targets another one.

After the discovery of aluminum residue on a recent victim, Catherine scans crime scene photos to see a neighboring house under construction. The foreman gives them the name of a man recently fired for looking at the neighbors. The team visits his house to find his family dead and a home video they presume he watched after killing them. They learn the general area of his current target and are able to find the exact house. Inside, the killer has cut the mother, but she opens the door for Catherine and they switch places. Catherine assumes the wife and mother role, cooks breakfast, and gets the killer to sit in front of the window at the kitchen table. He is killed by a police sniper. The situation affects both Thomas and Catherine. He promises his family to never let a case take precedence over them, and Catherine messages her mother to talk about Howard.

A killer uses enhanced hallucinogens in his methods, causing the team to work with the Narcotics Division and Catherine's former lover. Meanwhile, Thomas must revisit a case from which he based his book, as he receives post cards from the killer. Also, Catherine's mother is hospitalized after apparently having a stroke and falling down the stairs at home. Her condition worsens, and her family must make a difficult decision.

The team investigates the connection the killer has with his drug dealing, as he targets his next couple. Meanwhile, Thomas becomes paranoid trying to think like him. At her mother's funeral reception, Catherine is introduced to a boy being mentored by Howard. Suspicious, she is torn between investigating him and the murder case. This causes her to abandon Molbeck on surveillance and he is shot by the killer.

With Molbeck in the hospital, the police have stepped up their methods to catch the killer. Believing the killer will not change his dumpsites, all city park entrances become checkpoints. His vehicle passes inspection, as he has already disposed of a body. Knowing he can no longer use the vehicle, he allows his current captive victims to escape in it, only after he rigged it to explode. The FBI takes over the case, but Thomas and Catherine set a trap for the killer by publishing he is a copycat killer. They deliver him to Bisgaard. Meanwhile, Thomas tells Catherine to order the 9-1-1 call Howard placed when her mother fell down the stairs. When she listens to the call, she hears Howard speak to a boy in the house. Catherine believes her mother was killed when she discovered Howard raping the boy. Armed, she enters Howard's house, with Thomas pursuing her, while Howard waits inside with a gun. The sound of one shot fired is heard in the closing scene.