The trial is set for Oct. 13, officials said.
“We look forward to trying this case before Judge Williams," said Ritchie Rochelle of the Maryland State's Attorney's office. "The defendants have all entered not guilty pleas, which is their right. All defendants in this case are presumed innocent, until, or unless they are found guilty.”
Prosecutors said that Gray was arrested illegally and then transported without a seat belt in a police van while being restrained, according to the Baltimore Sun newspaper.
The ride led to Gray suffering a spinal cord injury. The officers did not respond to Gray's calls for medical assistance, prosecutors said, according to the paper.
In the wake of Gray's death, Baltimore erupted in riots amid a call for change in policing there.