Beth-Ellen Vinson, Rick Heath, lie detectors and cold cases

The Beth-Ellen Vinson case has been getting some renewed attention lately, 20 years after the disappearance and murder. Here's what happened:

Vinson left her apartment near North Carolina State University around 2:30 a.m. the morning of Aug. 16, 1994, and three hours later, police found her white 1990 Mazda 626 in front of a car dealership at 2501 Capita…