NASHVILLE, Tenn. – An Illinois truck driver suspected in the slayings of women at truck stops in several states waived his right to preliminary hearing in Nashville on Thursday and his case will go straight to a grand jury.

That prevented the prosecution from presenting any evidence against Bruce Mendenhall. Few details about his alleged crimes have been revealed beyond the first affidavit filed soon after he was arrested on July 12 and charged in the murder of a woman in Nashville.

The hearing was meant to determine whether there is enough evidence to keep Mendenhall in jail, where he is being held without bond.

His public defender, Amy Harwell, declined to say why he had waived his right to the hearing or otherwise comment on the case.

Mendenhall, 56, kept his head down as he appeared briefly in Davidson County General Sessions Court wearing khakis, a blue oxford shirt and shackled at the ankles. His responses to the judge’s questions were mumbled and inaudible to those sitting in gallery of the courtroom.

Mendenhall was charged with criminal homicide last month after being questioned by police at the same north Nashville truck stop where Sara Nicole Hulbert, 25, was found dead with gunshot wounds on June 26.

Police say he implicated himself in Hulbert’s death and at least five other similar slayings of alleged prostitutes at truck stops in Tennessee, Alabama, Georgia and Indiana when they first interviewed him. He has refused to talk to police since that time, a detective has said.

The affidavit in the Nashville case states that Mendenhall’s truck matched a description of a truck seen the night Hulbert was killed. Inside the truck police found what appeared to be blood on the inside of the driver’s door, inside a trash bag behind the driver’s seat and on Mendenhall’s left thumb.

At a subsequent press conference, a spokeswoman for the Tennessee Bureau of Investigation stated that the agency had retrieved hundreds of pieces of evidence from the truck but declined to describe them.

Mendenhall was also charged last week with killing Lucille “Gretna” Carter in Birmingham, Ala.

Investigators said the 44-year-old transient was shot and dumped nude next to a trash bin on a service road. She was found July 1 with a plastic bag over her head and duct tape around her neck. Mendenhall has not been charged in any of the other cases.

Law enforcement agencies across the country have contacted Nashville investigators to learn if Mendenhall could be involved in unsolved murders in their areas. The FBI has been creating a timeline of Mendenhall’s travels during his 20 years as a trucker to determine other cases in which he could be a suspect.

Relatives of Hulbert, who had two young children, appeared at the courthouse.

“We hope that this comes to an end soon,” said Roxanna Wayman, Hulbert’s sister. “And we are glad that if Bruce Mendenhall is convicted of these crimes, he will not be allowed to be back on the streets to do this to any other victim and no other family will have to go through what our family has endured.”