Police in Morenci, however, said that they still believe the boys are dead and their father disposed of their bodies. John Skelton pleaded no contest last year to charges of unlawful imprisonment, but he maintains that he didn't harm the children.
The boys were last seen at Skelton's home in Morenci, which is near the Michigan-Ohio border. Skelton didn't return them to their mother, setting off a search that involved hundreds of volunteers in both states.
Skelton told police he handed the boys over to a group he didn't identify to protect them from their mother.
"His choice to hide behind this outlandish story is selfish and cowardly," Morenci Police Chief Larry Weeks said in a statement. "If he cared about his sons at all he would disclose the truth and bring resolution to this case."
Investigators said they have received about 1,300 tips and continue to seek more, and a $60,000 reward is being offered. In the statement, police said: "The investigation remains active and at the forefront of our thoughts and prayers."
The National Center for Missing and Exploited Children created age-progressed photos of Andrew, Alexander and Tanner Skelton. The Skelton brothers were 9, 7, and 5 years old, respectively, when they last were seen.
The boys' mother, Tanya Zuvers, said recently that she hasn't given up hope for her sons.
(Click the photo for a full picture of all three boys.)