Associated Press Unidentified girls grieve for the victims of a school shooting in the Cathedral of Erfurt in Edfurt, eastern Germany, Saturday, the day after a former student killed 16 people and then killed himself in Gutenberg High School.

ERFURT, Germany ÷ The teen-age gun enthusiast who killed 16 people and himself at his former school enjoyed violent computer games and kept his parents in the dark about his humiliating expulsion from school, police said yesterday.

Adding new details to the troubling profile of Robert Steinhaeuser, the 19-year-old behind one of the deadliest school shootings ever, investigators said that hours before his deadly rampage, he told his parents he was going to take a math exam. As he left the house, his mother wished him good luck.

ăThe parents thought he was going to school every day and was successfully moving toward his high school diploma,ä Police Chief Rainer Grube said.

Officials said Steinhaeuser, an expert marksman, walked into the building just before 11 a.m., used a bathroom to change into all-black clothing and a ski mask, then fatally shot 13 teachers ÷ more than a third of the faculty ÷ two teen-age students and a policeman.

Police said he fired about 40 rounds before turning his 9 mm Glock pistol on himself inside the Johann Gutenberg Gymnasium.

Grube said authorities believe the killer had a Web site and were investigating a home page bearing his name and picture. But someone changed the page 12 hours after his death, Grube said, raising the possibility the current version is bogus.

In a search of Steinhaeuserâs home, police found comics filled with scenes of violence as well as a number of computer games that featured ăintensive weapons usage,ä Grube said. He said Steinhaeuserâs mother told police she had not noticed any unusual behavior in her son, described by officials and acquaintances as a loner with few, if any, close friends.

A quirk of Germanyâs education system also may have contributed to the tragedy. Thuringia, where Erfurt is the state capital, is alone in denying even an intermediate diploma to students who go beyond 10th grade, but then fail twice to pass final exams.

Officials said Steinhaeuser had failed last year, and his expulsion a few weeks ago for forging a doctorâs note deprived him of the second ÷ and last ÷ chance for a full diploma, necessary to attend a university or get a decent job.

Providing fresh evidence that Steinhaeuser was bent on killing teachers, police chief Grube said the witnesses recalled the gunman bursting into some classrooms but leaving if he saw no teachers. The two teen-age victims, a 14-year-old girl and a 15-year-old boy, were killed when Steinhaeuser fired through a closed door, Grube said.

Crowds continued to gather at the school entrance yesterday. Flowers overflowed from the steps onto the sidewalk, and candles sputtered in the rain. Foreign Minister Joschka Fischer became the latest national figure to pay his respects, placing a bouquet and consoling the tearful school principal as she told him about the horrific events.

Officials canceled classes for at least a week and said students would receive counseling at Erfurtâs city hall. The school remained sealed yesterday as police continued to secure clues.

Erfurt Mayor Manfred Ruge said after meeting the schoolâs parents and teachers yesterday that they had resolved to clean up and reopen the building as soon as possible to ăalso seize the chance to make a new beginning.ä