Knife

The Brandts are killed with a knife. The killer made precise stab wounds that cause the victims to bleed to death almost instantly.

Gun

The killer changes from a knife to a gun when the last two couples are murdered. This gun is traced back to Nicholas Jenks.

Tuxedo Jacket

The killer leaves behind his own tuxedo jacket after killing the Brandts. Police are later able to match the jacket with pants found in Nicholas Jenks's home.

Hair

A hair is found inside the body of Becky DeGeorge that establishes that the killer has a red beard.

Urine

The police find a puddle of urine at the first two murder sites and assume it belongs to the victims. However, Claire realizes by the positioning of the puddles, the urine must belong to the killer. Analysis of the urine also proves that the killer in the Brandt murders...