By Dan Kelley
PHILADELPHIA (Reuters) - The teen accused of a stabbing spree at a Pittsburgh-area high school in April that injured 20 students and a security guard waived his preliminary hearing on Monday and is headed for trial on charges of attempted murder, according to court documents.
Alex Hribal, 16, is accused of going on a rampage with two 8-inch kitchen knives in the halls of Franklin Regional Senior High School in Murraysville, about 20 miles east of Pittsburgh.
None of the victims, most aged 14 to 17, died from the injuries. At least two remained hospitalized for weeks after the attack.
Hribal, who is being held without bail at a juvenile detention facility, will be formally arraigned on July 23, according to court documents.
A sophomore at the time of the incident, Hribal has been charged as an adult and could face decades in prison if convicted.
A vice-principal who stopped the attack said Hribal refused to drop the knives he was carrying, and yelled: "My work is not done, I have more people to kill," court documents said.
Prosecutors say Hribal signed and dated a letter in which he laid out his plans for the rampage and wrote he looked forward to seeing the "helpless looks" on the faces of his victims.
Hribal's attorney, Patrick Thomassey, did not return calls for comment on Monday. He said previously his client was remorseful for the attack.
(Editing by Edith Honan and Peter Cooney)