GREENSBURG — A teen charged with stabbing 20 students and a security guard at his school will either stand trial or plead guilty Aug. 1, his attorney said after a pretrial conference Monday.

Westmoreland County District Attorney John Peck and the attorney for 18-year-old Alex Hribal met with a judge to hash out the next steps in the case.

Defense attorney Patrick Thomassey acknowledges that Hribal committed the crimes at Franklin Regional High School in Murrysville in April 2014 when he was 16. But he has argued that Hribal’s mental health issues spurred the attacks, which is why he wanted the case in juvenile court, where Hribal would face no sanctions after turning 21. Common Pleas Judge Christopher Feliciani rejected those arguments in May and last week refused to let Thomassey appeal that decision to the state Superior Court.

Peck told a Pittsburgh newspaper that he might offer a plea agreement before the August court date.

“We haven’t made an offer yet. I’ll be in touch with all the victims and explain the parameters of a potential sentence,” Peck told the newspaper. “I’ll get their input on what they think a deal should be.”