Death Maker

Death Maker, parts one and two, are the seventh and eighth episodes to air in the twenty-second series of Silent Witness, and the 199th and 200th episodes to air overall in the show. The episodes aired as following: Both parts of the episode were written by Marteinn Thorisson, produced by Kiaran Murray-Smith and directed by Mary Nighy. Richard Stokes served as the executive producer for both episodes.
 * Death Maker - Part One on 28 January 2019,
 * Death Maker - Part Two on 29 January 2019.

It is the next two episodes to air after episodes five and six in the twenty-second series: "To Brighton, to Brighton" and is followed by episodes nine and ten of the same series: "Betrayal".

Plot
As the Walsh family settle down for an evening meal, Les notices his mother, Olivia, is uneasy. In the kitchen, Les asks Olivia what is wrong. As Olivia prepares to open up to Les she is interrupted by the kids, who want dessert. After the meal, Olivia and Pat leave the house to go home. Olivia insists on driving due to the amount of alcohol Pat has had. She unlocks the car and as she opens the car door, the car explodes, killing her instantaneously. Jack identifies the use of a radio-controlled bomb as the cause of the explosion, and attempts to piece the device back together.

As the Walsh's house is being forensically examined Pat goes for a cigarette in the back garden. D.I. Jasper Quint goes to talk to Pat but notices he has run away. At the laboratory, sperm from Alex Harris is found in Olivia's intimate samples. The police go to interrogate Alex, who confesses that he had sex with Olivia three days prior to her death. Les goes to Pat's house to see if he can find him, but he is horrified when he opens the living room door to find a blood-splattered room. As Nikki, Thomas and Jack investigate they find a suitcase with blood stains inside it. The blood is Pat's. Jack and D.I. Quint are led to a storage unit when Clarissa finds branded storage tape under one of the suitcase wheels. At the storage unit the pair see a hooded figure carry the suitcase into one of the lockers. They locate the locker, and upon opening it find a fridge-freezer. Jack opens the fridge-freezer: it is empty. He does, however, find a serial code. The serial code is identified and the team discover it is anti-coagulated blood that was being stored in the fridge-freezer. The team also learn that Pat was on anticoagulants and was terminally ill from cancer. Thomas and Nikki realise that Pat has staged his own death.

Les, his wife Marie, and their two children: Rebecca and Danny, are placed in alternative accommodation for the time being. Danny gets upset when he realises that he has forgotten his favourite toy polar bear, so Les opts to head back to the house to get it. Once at the house, Les is denied access to the property due to forensic investigations still being carried out. Les heads back to his car where a gloved hand covers his mouth. Les's car then speeds into a car park and pulls up. Les stumbles out the car - he is with Pat. Pat tells Les he thinks he knows who killed Olivia, and at the same time reveals to Les he is dying of cancer. Les is stunned by his father's news, and agrees to help him in his mission to track down Olivia's killers.

Clarissa, Nikki, Jack and Thomas unearth the background of Olivia and Pat Walsh, and find that Pat was linked to a Northern Irish terrorist group from the 1980s. They believe this was the motive for murder, and that Pat was the intended victim. Jack appears to be affected by the case and visits his father, Conor. There, him and Conor discuss their past and how Jack's aunt was killed in an explosion in Ireland around the same time the Northern Irish terror group were active. The next day after work, Jack, alongside Clarissa, meet up with an old friend of his, Orla. Orla is a journalist who wrote articles on the Northern Irish terror group, and agrees to use her secret source to help the team identify if the terror group is active again. She meets up with Craig, who tells her to keep her nose out if she does not want to get caught up in the crossfire. In the evening, Pat visits William, his cousin. Pat consults William over the terror group and whether he knows anything about their involvement in Olivia's murder. He begins tying William to a chair as he makes him talk. William admits that the group is active again, but denies having any involvement in it. Pat does not believe William, and kills him, suffocating him by placing a plastic bag over his head.

The next day, William's dead body is found. Nikki finds a hair on William's clothing and believes it is not human. Jack finds a dog record in the cupboard confirming William owns a Staffordshire Bull Terrier. Nikki suggests that if the dog was present at the time of William's murder, it would most likely have attacked the killer. The dog is sedated and a blood sample found in its fur is taken. The blood sample is confirmed as belonging to Pat. Elsewhere, Les drives Pat to a car park and bandages Pat's bite wound up. Les tries to talk Pat out of trying to find Olivia's killers, but is unsuccessful. Pat walks off and Les follows.

Orla phones Jack as she continues to investigate whether the terror group are active again. However, as she is on the phone to Jack she is attacked. Jack and D.I. Quint race to Orla's house and find her unconscious, but alive. She is rushed to hospital. At the Lyell centre, Jack performs forensic tests on a notebook found at William's house. It reveals an address, which Jack and D.I. Quint head to. At the address, they find Orla and William's laptops, they realise Pat and Les have been there. Clarissa unlocks the laptops and finds a series of searches on William's laptop for personal information about Orla.

Meanwhile, Craig chauffeurs Ken and Geraldine back to their house. Once at their destination, Ken and Geraldine invite Craig into their house for a drink. There, they interrogate Craig on what he knows about the Irish terror group in relation to the ongoing investigations into Olivia's murder. At that point, the doorbell rings and Geraldine answers it. She walks back into the living room with two men, both in balaclavas, one of them pointing a  gun to her head. Craig, Geraldine and Ken are all tied to chairs and Pat reveals his identity to the trio. Pat tries to force a confession out of the three of them and how they planned to have Olivia killed, but Geraldine denies all claims and spits at Pat. Les also reveals his identity to Craig, Geraldine and Ken, but is stunned when he hears Geraldine reveal that Pat killed sixty innocent people in a bombing back in the 1980s. Police arrive at Ken and Geraldine's, and Les goes to open the door to them, but Pat shoots Les in the shoulder. Pat then walks back into the living room and prepares to kill Geraldine, but before he can Les intercepts, resulting in a scuffle and a shot being fired. The pair fall to the ground, but Les gets up. He's shot Pat. Armed police break into the building and arrest Les.

Back the the Lyell, Clarissa has finished going through Orla's laptop. Clarissa finds emails exchanged between Orla and Alex regarding the Irish terror group, prompting Alex to be arrested and Jack to head back to Alex's house to investigate further. In Alex's house, Jack finds a hidden room. Inside the hidden room are plans regarding the construction of a bomb. Jack sends the plans to D.I Quint and D.S. Anderson and the pair interrogate Alex. They notice that the plans for the bomb were the exact same as the improvised explosive device (IED) that Pat used to devise back in the 1980s. Whilst in the house, Jack notices that Alex ordered 500mg of an explosive material. Jack informs D.S. Anderson that 250mg was used to kill Olivia, and that only approximately 150mg remain - leaving 100mg unaccounted for. Alex confesses to killing Olivia, telling D.I. Quint he killed Olivia so that Pat would feel the pain that all the families, including him, felt when he killed innocent lives. D.I. Quint asks Alex where the unaccounted bomb is, and Jack realises that with Les in prison and Olivia dead, Alex has targeted Pat's grandchildren.

Marie, Rebecca and Danny arrive back at their house. The IED has been stuck to the inside of the door. Jack speeds to the Walsh's house to try and stop them from opening the door. Marie cannot find her keys and goes to look in the car, but Danny finds them in her handbag. He unlocks the door, just as Jack arrives. Marie receives a phone call from the police telling her not to open the door. She screams at the kids to not open the door as she runs towards the house. Jack pulls up outside the house at the same time, but as he runs towards the Walsh's house it explodes. Debris lies all around the house, and as Jack walks towards the house memories flood back to him from the day his aunt died. He finds Marie and the kids on the floor - alive.

Part One

 * Rebecca Walsh - Lila McNamara
 * Danny Walsh - Tommy Finnegan
 * Pat Walsh - Ian McElhinney
 * Olivia Walsh - Amanda Root
 * Les Walsh - Josef Davies
 * Marie Walsh - Lucinda Dryzek
 * Jack Hodgson - David Caves
 * Dr. Thomas Chamberlain - Richard Lintern
 * Dr. Nikki Alexander - Emilia Fox
 * D.I. Jasper Quint - Ray Fearon
 * Ken Lawson - Des McAleer
 * Geraldine Lawson - Simone Kirby
 * Reporter - Alex Jordan
 * Craig Greenwood - Sean Campion
 * D.C. Joan Anderton - Avita Jay
 * Clarissa Mullery - Liz Carr
 * Conor Hodgson - Richard Durden
 * Alex Harris - Silas Carson
 * Alice - Kiran Sonia Sawar
 * Storage Clerk - Perry Warner
 * Officer - Owl Young
 * Orla Flanagan - Emile Taaffe
 * William McDonagh - Gary Lilburn

Part Two

 * William McDonagh - Gary Lilburn
 * Jack Hodgson - David Caves
 * Dr. Nikki Alexander - Emilia Fox
 * Marie Walsh - Lucinda Dryzek
 * Rebecca Walsh - Lila McNamara
 * Danny Walsh - Tommy Finnegan
 * D.C. Joan Anderson - Avita Jay
 * Dr. Thomas Chamberlain - Richard Lintern
 * Alice - Kiran Sonia Sawar
 * Clarissa Mullery - Liz Carr
 * Pat Walsh - Ian McElhinney
 * Les Walsh - Josef Davies
 * D.I. Jasper Quint - Ray Fearon
 * Orla Flanagan - Emily Taaffe
 * Conor Hodgson - Richard Durden
 * Craig Greenwood - Sean Campion
 * Ken Lawson - Des McAleer
 * Geraldine Lawson - Simone Kirby
 * Alex Harris - Silas Carson
 * Harris' Lawyer - Shannon Murray

Deaths
Three characters died across the two episodes.
 * Olivia Walsh: blown up by an improvised explosive device designed to go off when she opened the car door.
 * William McDonagh: tied to a chair and suffocated when a plastic bag was placed over his head.
 * Pat Walsh: shot during a scuffle with Les Walsh.