TV Guide Investigation Discovery Monday

The presenter recalls how a psychiatrist and his adult son were killed execution-style. The case went cold until an attempted armed car robbery provided an odd link to the double murder

Buying goods from the comfort of home

Buying goods from the comfort of home

Buying goods from the comfort of home

Buying goods from the comfort of home

The case of 32-year-old Florida firefighter Brandy Hall, whose truck was found submerged at the bottom of a pond after she went missing in August 2006. There were traces of her blood inside the vehicle and a year later her backpack - minus her gun - was found in a canal. The FBI reviewed the evidence and decided Hall had likely been murdered, but the mystery of her fate remains

The Pennsylvania family decimated when masked men ambushed it at home with guns and crude bombs, killing a mother and her daughter. The shell-shocked survivors pointed the finger at one of their own, but lack of evidence stalled the case for 30 years

The case of mother-of-three Patty Vaughan, whose blood-stained minivan was found abandoned at a roadside on Christmas Day 1996, 20 miles from her home in Texas. Police considered the possible involvement of her ex-husband in her disappearance

The case of 25-year-old Corey Parker, who was excited about new opportunities when she moved to Jacksonville, Florida. However, a new friend stopped her before she could enjoy her new life

The case of 34-year-old Tara Lynn Grant, who was murdered by her husband Stephen in February 2007 after being initally reported missing. The case gained widespread attention, both in Michigan and the entire United States