Unknown (narrator or host)

On February 16, 2005, a local news station receives yet another package from the BTK killer.

Inside it, the item police had been hoping for, a computer disk.

Detective Randy Stone is a computer expert.

He slips the disc into his computer and opens the only file.

Stone determines the note was created using Microsoft's Office software.

The software is registered to a specific user.

In a matter of seconds, Detective Stone pulls up that name, as well as information on the author of the note itself.

Stone searches the internet for a Christ Lutheran church in Wichita.

In a matter of minutes, one man with a computer has ID'd a suspect and even provided his possible location.

Stone turns from his console to receive congratulations from fellow detectives.

Wichita detectives hit the street, zeroing in on Dennis Rader's home address.

Detectives Tim Ralph and Clint Snyder raced to Park City.

Even before they stopped the car, the pair get confirmation that Dennis Rader might actually be the killer known as BTK.

The Cherokee matches the vehicle seen in the parking lot of the Home Depot and linked to BTK.

Some detectives want to move in immediately and arrest Rader.

Lieutenant Landwehr, however, tells his men in the field to stand down.

Lieutenant Landwehr wants to know as much as he can about Rader before moving on the suspect.

Investigators begin to turn over the ground in Rader's personal life to see what might lie underneath.

For a serial killer, blending in is essential, enabling him to kill for years without being detected.

Landwehr orders 24-hour surveillance on Rader.