A fifth student has died after being shot by a gunman who later killed himself at a university in the US state of Illinois.
At least 13 others were wounded after the gunman opened fire with a shotgun and pistols in a crowded lecture hall at Northern Illinois University, 100km west of Chicago.
Witnesses said he opened fire after stepping out from behind the curtain at the front of an auditorium at the end of a geology class.
Police were in the room within two minutes of getting the call but did not have time to fire a single shot as the gunman was already dead on the stage.
The gunman was identified today as Stephen Kazmierczak, 27, described as an 'outstanding' graduate student with no signs of a troubled mind.
'It started and ended within a matter of seconds,' university police chief Donald Grady said at a press conference.
Mr Grady said there were 'no red flags' to predict Mr Kazmierczak's fatal outburst.
Witnesses said the gunman, dressed in black, said nothing before he began firing.
All of those shot were students, including the lecturer who was a graduate student.
It was earlier reported that six students died after being shot, but the number has been revised down to five after a miscommunication with the hospital was cleared up.
Six victims remain in critical condition while eight were discharged within a few hours.
Mr Kazmierczak was enrolled as a graduate student in sociology last year and then transferred to another state institution.
The shooting comes 10 months after 32 students and faculty were shot down by a student at Virginia Tech University in the deadliest massacre ever at a US school.
Northern Illinois University was placed on a security alert in December after police found threats on a bathroom wall with racial slurs, references to the Virginia Tech shooting and a warning about the final days of the semester.
Northern Illinois University, chartered in 1895, is a teaching and research institution with a student enrollment of more than 25,000 and nearly 1,300 teachers.
