HIGHLIGHTS: Reports about a Second Assailant Being Investigated.
Attack Upsets German Sense of Security. 
Killer Expelled From School Several Months Ago.

STORYA student bent on bloody revenge after being expelled from his school shot dead 17 people, mostly teachers, before killing himself on Friday in the worst murder spree in post-war Germany.

Armed with a pump-action shotgun and a handgun, the 19-year-old man, masked and clad in black, walked calmly through the Gutenberg high school in the eastern town of Erfurt, pumping bullets at teachers he found in the corridors and classrooms.

He killed 14 teachers, two pupils, a police officer and then himself. Six others were wounded.

A number of students who escaped unharmed from the school said a second gunman had been in the school. Police said late on Friday they were investigating the reports and added they could not rule out the possibility a second assailant had escaped.

More than 1,000 mourners attended sombre ceremonies in a cathedral and a nearby church.

The scale of the murder, rivalling some of the worst school killings in the world, stunned Germans, whose sense of security was upset just two weeks ago by the deaths of 11 German tourists in a bomb blast in Tunisia.

Chancellor Gerhard Schroeder said he was staggered by the crime and cancelled an election campaign event planned for Saturday. Flags on the Reichstag parliament building in Berlin flew at half-mast.

The killer, who has not been named, was expelled from the school several months ago and banned from taking his "Abitur", a high-school exam required for entry into university.

PHOTO CAPTION

Police cars are seen in front of the Gutenberg-Schule school in the German Thuringian state capital Erfurt. Eighteen people were killed there on April 26 when a former pupil opened fire. REUTERS/String