For three decades, the BTK killer terrorized Wichita, Kansas, taunting investigators like an untouchable phantom. His desperate need for infamy eventually triggered a fatal mistake. Dennis Rader asked police if a floppy disk could be traced. Detectives lied, assuring him it was secure. Confident, Rader mailed a disk to a local television station, believing he had outsmarted everyone. Instead, forensic experts immediately recovered the files' deleted metadata. Hidden within the code were two damning clues: the name Dennis and a link to Christ Lutheran Church. That single digital breadcrumb unmasked him, leading directly to his 2005 capture and ending a 30-year nightmare.