Here are the key events which led up to and followed the murders of Katie Edwards and her mother Elizabeth at their home in Spalding, Lincolnshire.
- Lucas Markham and Kim Edwards meet in a queue for an IT lesson and start going out with each other. They are said to get on well because of a bleak but shared outlook on life.
Monday October 12 2015
- The teenagers run away together after he is given a detention at school, taking clothing, food, bicycles and a tent with them.
- Police appeal for sightings of the pair in Spalding, or nearby villages Cowbit and Crowland, and announce five days later that they have been found safe and well.
Thursday March 17, 2016
- Edwards, who had been assessed by mental health professionals after expressing suicidal thoughts, makes an attempt on her own life and spends two days in hospital.
Sunday April 3
- Ten days before committing murder, Edwards shares a late-night exchange with her mother on Facebook after changing her profile picture.
- After being asked "Where's your beautiful smile x", Edwards replies "It disappeared x." Mrs Edwards then asks "Why Hun x" and adds "I think it's under ur bed lol x."
Saturday April 9
- Markham and Edwards barricade themselves into his room after her mother tells her she will turn out like her absent father - described in court as a drug addict.
- The couple do not leave the room until they climb out through a window at 2pm the following day.
Monday April 11
- During a conversation in the back garden of the Edwards' family home, Markham and his girlfriend agree to kill her mother and sister,
- mapping out a detailed plan to stab them through the voice-box to stifle their screams. They agree that he should knock three times on a rear window, before climbing into the property through a bathroom window opened by Edwards.
- Markham later goes to the house but Edwards falls asleep and he is unable to get into the property.
Tuesday April 12
- Edwards again falls asleep, meaning Markham is unable to enter her home.
Wednesday April 13
- At about midnight Edwards hears three knocks on the window of the bedroom she shares with Katie. She lets Markham into the bathroom and he passes her a bag containing spare clothing and four knives.
- Although the original plan is for Markham to kill Elizabeth Edwards and for Edwards to stab Katie, Markham offers to kill both victims after his girlfriend says she does not want to kill her sister.
- Markham then smothers and stabs both victims through the neck.
Thursday April 14
- Edwards and Markham are reported missing to the police by their school and his aunt. Despite the teenagers being inside 5 Dawson Avenue, knocks at the door by relatives and police go unanswered at 5.10pm, 9pm and 9.46pm.
Friday April 15
- Police force entry to 5 Dawson Avenue and find Mrs Edwards and Katie dead in their beds. Both defendants are arrested on suspicion of murder.
Saturday April 16
- Edwards makes full admissions to police, giving them a step-by-step account of the murders and their planning. The girl tells two detectives the plan was fully agreed between her and her boyfriend.
- She tells them: "We made sure we were both definitely like OK with with it and he continuously asked me if I still wanted to go through with it and I said yes. We went over the plan over and over again."
Sunday April 17
- Both teenagers are charged with two counts of murder.
Tuesday September 6
- Edwards and Markham both admit manslaughter but plead not guilty to murder.
Monday October 10
- Markham admits murder and is remanded in custody awaiting sentence at the end of Edwards' trial. Prosecutor Peter Joyce QC tells Nottingham Crown Court Edwards accepts that although Markham stabbed the victims, she is equally responsible for the deaths, having planned them and helped to put the plan into action.
- Mr Joyce tells jurors the only issue in the case is whether Edwards has a defence of diminished responsibility.
Tuesday October 11
- Edwards is found guilty of murder by a unanimous verdict.
Thursday November 10
- Edwards and Markham are both given life sentences with minimum terms of 20 years by High Court judge Mr Justice Haddon-Cave. The judge tells the teenagers: "The killings were brutal in the form of executions and both victims, particularly Elizabeth Edwards, must have suffered terribly in the last minutes of their lives."
Friday June 9, 2017
- Their minimum terms are reduced to 17 years the Court of Appeal which also rules they can be named.