The father of three missing Michigan boys said he gave his sons away for them to live on a farm in Ohio, according to a new interview. Andrew Skelton, 9, Alexander Skelton, 7, and Tanner Skelton, 5, have been missing since November 2010.

John Skelton said he gave the boys to three adults – two women and a man – according to an interview with WDIV-TV published Monday. Skelton said he gave the children away to what he called “the underground sanctuary” so that they could have a better life.

Skelton spoke to WDIV from the Bellamy Creek Correctional Facility in Ionia County, where he remained behind bars on charges of unlawful imprisonment.

“I miss their voices,” Skelton said.

The case of the missing Skelton brothers has recently come back into the public eye after a box of bones believed to have belonged to three siblings was discovered in Montana in September. The bones were undergoing DNA testing to determine whether they might have any connection to the Skelton brothers.

“While it’s very interesting, and something we’re following up with big time, we haven’t seen any other connections [that would link the cases],” said State Police Det. LT. Jeremy Brewer, according to USA Today. The testing was expected to take anywhere from three to six months.

The Skelton brothers went missing from Morenci, Michigan, southwest of Detroit, on Black Friday 2010. Tanya Skelton said her husband, John Skelton, was supposed to return the boys to her but never did, according to WDIV. John Skelton, meanwhile, always maintained that he gave the boys away. John Skelton also claimed that Tanya, who was charged with misconduct for having sex with a 14-year-old boy in 1990, was abusing her sons. She denied she abused the boys.

The children were never found.

Seven years later, the case remains open and investigators continued working to locate the siblings.

“As a police officer, you know, you’re realistic,” Brewer said in November, according to WDIV. “You have to be realistic because you’ve had cases that some are solved and some are not. On a case like this, with the magnitude, with the resources we have directed towards ti, I firmly believe without a doubt that we will get some type of closure on it one day.”

Skelton Brothers Andrew, Alexander and Tanner Skelton went missing in 2010.