See more of the story

Oct. 22, 1989: Jacob Wetterling, 11, is abducted by a masked man on a road near his house in rural St. Joseph, Minn., while returning from a Tom Thumb store with his brother, Trevor, 10, and friend Aaron Larson, 11.

Dec. 16, 1989: Daniel Heinrich is interviewed by the FBI. He said he couldn't recall where he was on the day Jacob disappeared.

Jan. 12, 1990: Heinrich is re-interviewed by law enforcement. They focus on a pair of tennis shoes and car tires. He also volunteered body hair samples for testing.

February 1990: With others' help, Patty and Jerry Wetterling establish a foundation in their son's name to bring attention to child abduction and abuse.

August 1994: Patty Wetterling lobbies for a bill that requires states to create sex offender registration programs.

Sept. 13, 1994: Congress passes the bill that includes the original Jacob Wetterling Sex Offender Registration Act.

October 1998: Patty Wetterling writes an open letter to Jacob's abductor, asking that he tell her what happened to her son. The letter is published in several newspapers and on the Internet, resulting in several significant leads.

Over the years, investigators have followed up on more than 50,000 leads from Minnesota to Europe. They have talked with psychics, checked sightings of Jacob look-alikes and cleared more than 4,000 suspects.

Feb. 17, 2010: 32nd anniversary of Jacob's birth.

July 2010: Authorities use earth-moving equipment to search a farm where Jacob was last seen.

October 2014: Billboards go up in the St. Joseph area urging people to call authorities if they have any information about Wetterling. It features a picture of him in 1989 and an illustration of what he would look like at age 36.

July 10, 2015: Heinrich's DNA is found on the sweatshirt of a Cold Spring boy who was abducted and sexually assaulted in 1989.

Sept. 1, 2016: Authorities recovered unidentified remains after Heinrich agreed to cooperate and provide information, according to authorities.