SPRINGFIELD, MO. ? Gregory Breeden, once suspected in the deaths of seven women whose bodies were dumped in the Missouri River, has pleaded not guilty to a federal charge of threatening a judge.

Breeden, 58, was charged last month in an indictment unsealed the day after he finished serving a 10-year sentence on bad-check charges. He has denied any involvement in the killings of the seven women, but prosecutors have kept him behind bars by convicting him on other charges, such as violating probation, whenever he was able to return to Kansas City.

The FBI began investigating Breeden in August after hearing from the Missouri Department of Corrections that Breeden had threatened U.S. Magistrate William A. Knox, of Jefferson City, and corrections employees.

At a detention hearing Tuesday in Springfield, U.S. Magistrate James C. England heard testimony on the government’s request to keep Breeden in custody while awaiting trial in January. England did not immediately issue a ruling.

In August, Knox ruled against Breeden in his lawsuit seeking early release from prison. Breeden had said he wanted to get out early so he could see his daughter before she went to Iraq with the U.S. Marine Corps.

FBI agent Cody Abram testified at the detention hearing that agents met with another inmate at the Tipton Correctional Center who told them Breeden was trying to raise $100,000 to hire somebody to kill Knox. The inmate agreed to wear a recording device and talk with Breeden again, but later told agents Breeden had changed his mind.

“The individual reached out to the FBI and said he (Breeden) didn’t want the judge killed,” Abram said. “He wanted the judge incapacitated in a vegetative state.”

Transcripts of recordings that prosecutors said were made of Breeden were read at Tuesday’s hearing.

One, made on Aug. 17, showed Breeden talking about how a “sleeper hold” could be used to disable the judge. The transcript also showed Breeden calling the judge a “piece of garbage” in love with his own power.

Breeden, who lived in the Kansas City area, had been a suspect in the deaths of seven women whose bodies were found in the Missouri River between 1982 and 1994. He was charged in only one of the deaths, and that case was dropped in 1999 at the request of a special prosecutor who said a key witness would no longer cooperate.