DETROIT -

A Michigan man whose three sons have been missing since last year has been sentenced to 10 to 15 years in prison on charges of unlawful imprisonment.

John Skelton's sons -- 9-year-old Andrew, 7-year-old Alexander and 5-year-old Tanner -- have been missing since Thanksgiving, when their mother said Skelton never returned them to her after a scheduled visit.

The father pleaded no contest to the charges in June, after prosecutors dropped kidnapping charges. He has said he gave them away to an organization because they were being abused by their mother. Hundreds of people have searched woods and waters in Ohio and Michigan. In February, Morenci Police Chief Larry Weeks, concerned that people had false hope of the boys' return, said the case had turned into a homicide investigation.

Skelton appeared Thursday in Lenawee County Circuit Court in Adrian. He told Judge Margaret Noe he loves the boys and has cried daily since their disappearance.

Noe told Skelton his "explanations have been ridiculous."

"Because of you, Andrew, Alexander and Tanner have been silenced. We don't know where they are," Noe said.

Assistant prosecutor Douglas Hartung asked Skelton if he would make one last statement about where the boys were.

"The only question left is, are you man enough to tell the truth? Once and for all," Hartung said.

Skelton never answered the question. Instead, responded, "I would have done things differently if I felt that the system didn't fail me, if I felt the people who were supposed to have done something didn't choose friendship over their duty.That's it."

Noe exceeded the sentencing guidelines, which were 43 to 86 months. Skelton was given credit for 289 days already served.

Tanya Skelton filed for divorce last September. The boys lived with her but were allowed to visit with their father.