Former Bixby Energy Systems CEO Robert Walker will remain behind bars until his fraud trial, a judge has ruled.

U.S. Magistrate Judge Jeanne Graham, in an order filed Wednesday, denied a defense request to release Walker, 71, and place him under home detention because his health has deteriorated and he could better prepare for trial outside of jail.

Walker has pleaded not guilty to charges of mail fraud, wire fraud, tax evasion, conspiracy and witness tampering. In August, while on conditional release, Walker was arrested and ordered back to jail after the alleged witness tampering attempt was discovered by investigators.

Walker is accused of bilking 1,800 investors, business partners and customers of the failed Ramsey-based company, pitching a "clean coal" technology that federal officials say he knew never worked. His trial is set for January in U.S. District Court in Minnesota.

David Shaffer