(Adds scheduled court appearance 11th paragraph)
By Elizabeth Daley
PITTSBURGH, April 14 (Reuters) - Teachers and staff returned on Monday to the Pittsburgh-area high school where a stabbing last week left 22 people injured, in preparation for the resumption of classes.
Four critically injured boys remained hospitalized following the attack last Wednesday at Franklin Regional High School in Murrysville.
A 16-year-old student at the school, Alex Hribal, has been charged as an adult with attempted homicide and aggravated assault.
Students are expected to return to school on Tuesday to meet with teachers and attend counseling if needed, and classes are set to resume on Wednesday, according to the school district's website.
School officials sought privacy, asking members of the media to stay away.
"As we begin our recovery phase, it is imperative that the district begins to create a normal and calm educational environment for our students who are currently on campus and for those who will be returning to Franklin Regional Senior High School," read a statement on the website.
Of the four teens still hospitalized, a 17-year-old student underwent his fourth surgery at UPMC Presbyterian Hospital on Sunday, according to the hospital's Twitter feed.
Three other students remain in intensive care at Forbes Hospital, according to hospital spokesman Jesse Miller.
No motive has been attributed publicly to Hribal, who is accused of walking his school's hallways, stabbing and slashing classmates with two 8-inch kitchen knives.
A security guard and 21 students were wounded before Hribal was tackled by an assistant principal.
Hribal is scheduled to appear in Westmoreland County Magisterial Court on April 30 before Judge Charles Conway.
His attorney, Pat Thomassey, has said the victims were not specifically targeted and that his client expressed remorse, although he said he did not know what his motive might have been. Thomassey could not be reached for comment on Monday. (Editing by Ellen Wulfhorst, Leslie Adler and Lisa Shumaker)