A Missouri man goes missing, and his ex-wife holds the key to the mystery.

A nurse's life is turned upside down when her husband is murdered and a secret video shows that she's hiding something from police. (also shown as S8:E16) (original aired S6:E16)

A business woman's life becomes a sci-fi tale, when her new boyfriend's ex is abducted and clues point toward an extraterrestrial motive. (original aired S6:E15)

A toxic mother-daughter relationship spills over to the men in their lives, with deadly consequences. (also shown as S8:E3)

A popular professor's death looks like an accident, but turns into a murder mystery with his widow at the center. (original aired S6:E18)

A modern-day Romeo and Juliet story has a killer ending. (also shown as S8:E4)

A fitness queen turns fugitive when her assistant's body turns up in her car. (also shown as S8:E5)

A military wife is caught in deadly love triangle. (original aired S6:E17)

The premature death of a cancer victim leaves his wife facing lethal injection. (also shown as S8:E7)

A woman eludes police for six years after a confrontation with her neighbor turns deadly. (original aired S6:E12)

A young woman's scrapbook offers insight into a shocking crime. (original aired S6:E11)

A yoga instructor's death reveals his girlfriend's secret double life. (also shown as S8:E10)

Two bodies in the back of a burning car lead police to the door of a police officer's wife. (also shown as S8:E11) (original aired S6:E2)

A teen love triangle ends with a missing girl, a dismembered body and three families changed forever in East Moline, IL. (also shown as S8:E12)

Forced to choose between her mother and her boyfriend, a Florida teen makes a deadly decision in West Palm Beach, FL. (also shown as S8:E14)

A young girl's death is complicated by her lesbian lover -- and her lesbian lover's husband in Easton, PA. (also shown as S8:E15)

In Greeley, CO, the motive behind the execution-style murder of a police officer's wife puts a dark new twist on the term "internal affairs." (original aired S6:E25)

In Akron, OH, a beauty queen ends up in the spotlight when a local murder reveals her scandalous secret life, but was she wrongly accused? (original aired S6:E9)

A man awakens alone to find a knife-wielding man in his bedroom -- but is his absent wife a victim or an accomplice? (original aired S6:E10)

In 2005, a wife accidentally shot her police officer husband with his service weapon. But, when police learned the grieving widow had also embezzled money from her church to cover the family's debt, was her husband's life insurance a motive to kill? (original aired S6:E8)

In Boynton Beach, FL, a beautiful young woman is caught on tape plotting to kill her husband -- but was it real or an audition for reality TV? (also shown as S8:E18)

A case study of an Arizona woman who was convicted of the August 2007 shooting death of her husband. (also shown as S8:E19)

A chemist, a dying husband and a suicide add up to a murder mystery in Raleigh, NC. (original aired S6:E21)

In Clearwater, FL, a businesswoman seeks revenge and ends up a fugitive. (also shown as S8:E21)

In Farmington Hills, MI, a popular elementary school teacher is accused of murdering her husband with an axe. (also shown as S8:E22)

In Alexandria, KY, a bookkeeper gets behind on taxes for the family business, and her husband turns up dead before he can learn about her secret. (original aired S5:E2)

In Toronto, a Canadian woman gets caught up in a love triangle... and a murder investigation. (also shown as S8:E24)

A preacher and his wife looked like they had a marriage made in heaven -- until a body was found in the parsonage. Was it cold-blooded murder or something else? (original aired S6:E1)

In Nashville, TN, it's murder for her marriage when a woman's secret lover comes out of the closet. (original aired S5:E1)