A southern Illinois farmer pleaded guilty Wednesday to federal bankruptcy fraud charges, and his attorney said outside court that his client had nothing to do with the unsolved killings of a potential witness and his wife.

Joseph Diekemper, 60, of Carlyle, pleaded guilty to conspiracy to commit bank and mail fraud, making a false statement to the Department of Agriculture and perjuring himself during earlier bankruptcy proceedings.

His wife, Margaret Diekemper, 64, pleaded guilty last week to a federal charge of conspiring with her husband to commit bankruptcy fraud and agreed to help authorities.

Assistant U.S. Attorney Jennifer Hudson would not comment after Wednesday's hearing. However, federal prosecutors have said Diekemper filed for bankruptcy in 2004, then hid farm equipment, allowed vehicle titles to be put under other people's names and fraudulently obtained agricultural subsidies on land that already had been turned over to a creditor.

As part of the scheme, authorities say, Diekemper stashed a tractor behind a false wall in an outbuilding on property rented by George and Linda Weedon.

The Weedons were found shot to death in April 2007, just days after George Weedon approached the FBI about the tractor and told an investigator he worried Joseph Diekemper would burn down his house if he ever found out, according to an FBI memo filed in the fraud case. When the couple's bodies were found, their rental home was ablaze.