Feb. 15 (Bloomberg) -- Authorities searched for a motive after a former student armed with a shotgun and three pistols opened fire in a Northern Illinois University lecture hall, killing five people and injuring 16 before shooting himself dead.

The gunman, clad in a black trench coat and beanie hat, emerged from behind a curtain and fired more than 50 shots yesterday into the geology class at the school's DeKalb campus, about 65 miles (104 kilometers) west of Chicago, school officials and witnesses said.

``It started and ended within a matter of seconds,'' university Police Chief Donald Grady said at a televised news conference yesterday. ``We have no apparent motive.''

Grady identified the gunman today as Stephen Kazmierczak, 27, a graduate student in sociology who left NIU after less than a year to attend the University of Illinois. He had been taking medication for an unidentified condition, although he had stopped and become erratic in the past two weeks, Grady said.

``There were no red flags,'' Grady said. ``He was an outstanding student, he was an awarded student, he was someone who was revered by the faculty and staff and students alike.''

Virginia Tech

Kazmierczak was a native of Elk Grove Village in suburban Chicago and a graduate student in the University of Illinois School of Social Work on the Urbana campus, the school said in a statement posted on its Web site.

University of Illinois police said they had no contact with Kazmierczak, who had an office on the Urbana campus.

The attack came 10 months after a student at Virginia Polytechnic Institute and State University in Blacksburg, Virginia, killed 32 students and teachers before committing suicide in the deadliest shooting rampage in U.S. history. That shooting prompted campuses nationwide to reassess their security and notification practices.

NIU President John G. Peters told reporters there was no reason to believe yesterday's incident was related to threats scrawled on a campus bathroom wall in December referring to the Virginia Tech massacre.

``We are dealing with a disturbed individual who intended to do harm on this campus,'' Peters said in a televised press conference this morning. ``We did everything we could to ensure the safety of this university, and we are going to continue in that vein.''

`No Expression'

Kazmierczak ``had no expression on his face whatsoever'' when he entered the classroom, senior George Gaynor, 23, a geography major from Homer Glen, Illinois, told reporters. ``The look on his face is something I will remember.''

About 150 to 200 students were in the Cole Hall lecture room when the shooting began shortly after 3 p.m. local time, student Paul Sundstrom said in a televised interview posted on MSNBC.com.

``This guy came in from behind where the professor was speaking and began shooting,'' Sundstrom said. ``He shot, emptied out the gun, and nonchalantly began reloading.''

Officers reached the lecture room within two minutes, yet the gunman had already killed himself, Grady said. All classes were canceled 20 minutes later and by 4:10 p.m. the school said the danger had passed, according to the university's Web site.

Mostly Silent

Grady said officers recovered 48 shell casings and six shotgun shells. According to Kevin Cronin of the U.S. Bureau of Alcohol, Tobacco and Firearms, Kazmierczak had legally purchased the shotgun and one of two 9-millimeter pistols on Feb. 9 in Champaign.

The campus was mostly silent today, with temperatures hovering around 15 degrees Fahrenheit (minus 9 Celsius) and members of the media and law enforcement officers appearing to outnumber students. On a snowy hillside not far from Cole Hall, a makeshift memorial was erected to the victims -- five white crosses adorned with red roses and the names of the victims.

``A lot of folks today will be praying for the families of the victims and for the Northern Illinois University community,'' U.S. President George W. Bush said. ``It's obviously a tragic situation on the campus, and I ask our fellow citizens to offer their blessings, blessings of comfort and blessings of strength.''

Christopher Morlin, a 22-year-old junior mechanical engineering student from Rockford, said he thought the telephone call telling him about the shootings was a joke until he looked out his dorm room window and saw people reacting.

``We should all be prepared for a situation like this,'' Morlin said.

Regular Updates

In the Virginia Tech attack, university officials were criticized by a state panel for waiting almost two hours before warning students in an e-mail message about a ``shooting incident.''

NIU students were given regular updates and warned to find a ``safe area'' by the university's alert system. The DeKalb campus has 25,000 students.

``It appears that they did have a safety program in place,'' said Carolyn Reinach Wolf, a founder of Campus Behavioral Health Risk Consultants LLC, which addresses security and mental health legal issues on campuses. ``Since Virginia Tech, campuses across the country have been reviewing their safety plans.''

Killed were four women and a man, and the injured were taken to Kishwaukee Community Hospital, where two people were listed in stable condition today. Seven patients in critical condition were transferred to other hospitals, and eight were discharged, according to the hospital's Web site. The school today corrected a previous report that the gunmen had killed six people.

The victims, all from Illinois, were identified as Daniel Parmenter, 20, of Westchester; Catalina Garcia, 20, of Cicero; Ryanne Mace, 19, of Carpentersville; Julianna Gehant, 32, of Mendota; and Gayle Dubowski, 20, of Carol Stream.

To contact the reporters on this story: Chris Dolmetsch in New York at cdolmetsch@bloomberg.net; Andrew Harris in DeKalb, Illinois, at aharris16@bloomberg.net.

Last Updated: February 15, 2008 14:07 EST