In broad daylight on a busy Woolwich street on May 22, 2013, serving soldier Fusilier Lee Rigby is attacked and murdered by Islamic extremists Michael Adebolajo and Michael Adebowale.
Oakley, KS: Alice Pepperl is found dead in her motel room, and a missing quarter is the only way to connect her to her killer. (S1, ep 12)
Drug dealer Dale Cregan hits the headlines in 2012 when he murders police officers Nicola Hughes and Fiona Bone. Dermot Murnaghan examines the tragic case.
Victims and police discuss the string of historic indecent assaults committed by beloved entertainer Rolf Harris who, in 2014, is sentenced to prison time over a number of sexual offences.
In 2012, Mick and Mairead Philpott were charged for the murders of six children that died in a house fire.
In 1989, 51 lives are lost when the pleasure boat Marchioness collides with the dredger Bowbell and sinks.
Beverley Allitt was thought to be a 'model' nurse. Very astute, caring and always willing to help, discover why she murdered four children and attempt to kill 11 others.
The wife of Garry Newlove, who was beaten to death outside his home in Cheshire in 2007, looks back at the night of her husband's murder.
Bonnyville, AB: Investigators are stumped when businesswoman Doreen Bradley is found murdered in her rural home, until the DNA of an unknown person is uncovered. (S2, ep 10)
Verdigre, NB: Just outside of Verdigre, Nebraska, a domestic altercation ends in death. Frances Thompson claims to have killed in self-defence, but investigators aren't so sure. (S2, ep 2)
Armstrong, BC: A Halloween murder shocks the community of Armstrong, BC. With little more than a composite sketch to go on, investigators work to bring the killer to justice. (S2, ep 8)
Sparta, MI. A town mobilises when a young mother doesn't come home after Christmas shopping. (S1, ep 1)
Enderby, BC: Authorities are up against it as they attempt to unlock the clues and solve the horrendous double murder of a beloved dairy farming couple with no clear suspects. (S2, ep 7)
Athens, WI: Authorities contend with multiple theories after Kenneth Kunz discovers four of his family members murdered and one missing. (S1, ep 1)
Brandon, MB: When Erin Chorney disappears without a trace, investigators go to exceptional lengths to discover her whereabouts. (S1, ep 4)
Yellow Grass, SK: When Abbie Speir's body is pulled from her burning house, investigators discover the fire is no accident and believe the killer could be lurking close to home. (S2, ep 13)
Hurd: The tragic story of Anna Hurd, who was murdered by her 'clingy and controlling' boyfriend Anthony J Mitchell after she tried to break up with him. (S1, ep 5)
Evans: The disturbing story of Alan Evans, who tried to get away with murdering his wife by pretending she had fallen down the stairs, after she found out about his affair. (S1, ep 6)
Garbutt: In 2010, Robin Garbutt called 999 to report that his wife had been murdered by an armed robber in their home. But flaws were quickly found in his version of events. (S1, ep 7)
Wilson: Farmer Robert Wilson told police he had accidentally run over his wife with a tractor. But in reality, he was leading a double life and murdered her in cold blood. (S1, ep 8)