US school knife horror still a mystery

The motive for a horrific knife rampage at a Pennsylvania high school remains a mystery because the teenage suspect is not talking and many of the victims remain in hospital, police have said.

Alex Hribal, 16, is accused of maiming 21 pupils and a guard at the 1,200-student Franklin Regional High School in Murraysville, east of Pittsburgh, on Wednesday. The charges against him include four counts of attempted murder and 21 counts of aggravated assault.