BRIGHTON -- An Adams County Court judge declared a mistrial in the case of Jeremy Webster.  

Webster is accused of killing a 13-year-old boy during an alleged road-rage incident in June 2018. The incident, which also injured the boy's mother, his younger brother and a bystander, was at a Westminster dentist's office.

Chris Hopper, spokesman for the 17th Judicial District Attorney's Office, said an emergency medical issue prevented a prosecution witness from coming to Colorado to testify in person at the trial. Hopper called the witness "necessary and indispensable" to the prosecution's case.  Jury selection was ongoing. The trial began July 7.

The judge, Priscilla Loew, reset the  proceedings to Oct. 25. 

Webster is charged with a total of 22 counts, including murder with extreme indifference and assault with extreme indifference.