Sources told FOX News' Rita Cosby the following are tips that led to an arrest in the 30-year-old BTK case:

The alleged murderer sent photos last March of one of his victims, Vicki Wegerle, whom was strangled in 1986. Photos showed her bound at the crime scene, causing cops to review certain forensics and crime scene information.

Cops traced a license plate seen on surveillance tapes of a point where the suspect dropped off one of his packages to the man in custody. Law enforcement kept watch of the suspect and locations he frequented for some time.

Finally, ample amounts of DNA samples saved from the crime scenes, most of it from the 1974 crime scene of an 11-year-old female victim, confirmed the match to the man currently in custody.