Several key elements helped authorities solve the decades-old abduction of Jacob Wetterling.

Jacob was 11 when he was abducted from a rural road near his home in central Minnesota on Oct. 22, 1989. On Tuesday, 53-year-old Danny Heinrich admitted he abducted, sexually assaulted and killed the boy, then buried his body.

Among the key factors, authorities took a fresh look at the case in 2014, as the 25-year-anniversary of Jacob’s abduction approached. A new investigator began reviewing all of the evidence, and advanced technology was used to re-test old evidence.

The DNA on the sweatshirt of another assault victim matched Heinrich, setting many other things in motion, including a search of Heinrich’s property.

Heinrich pleaded guilty Tuesday to one count of child pornography. He won’t be charged with Jacob’s murder, but he led officials to his remains and confessed as part of his plea deal.