The 17-year-old gunman who went on a rampage at his former school and killed 15 people before taking his own life gave a warning in an Internet chatroom only hours earlier and said he was "sick of this life," officials said yesterday.

Suspect Tim K. told others in the chat room he planned to attack his school in Winnenden, said Baden Wuerttemburg state Interior Minister Heribert Rech. Rech said the suspect wrote, "You will hear from me tomorrow, remember the name of a place called Winnenden."

In the first indication of a motive in the shooting, Rech said the teenager told others in the German-language chat room that: "Everyone laughs at me, nobody recognizes my potential."

"I'm serious. ... I have a weapon here," Rech said the youth wrote. "Early tomorrow morning I will go to my former school."

Rech said the chat had occurred the night before the attack, but a police official, Erwin Hetger, later said it was in the early morning on Wednesday, about six hours before the 9:30 am shooting.

The youth ended the chat saying, "No reports to the police now, don't worry, I'm just baiting you."

A Bavarian man told police about the chat after the school shooting in Winnenden had taken place, Rech said. He told authorities his 17-year-old son only told him about it after seeing the news reports and had not taken the threat seriously, replying to the message: LOL - shortform for "laughing out loud."

Local media have identified the gunman as Tim Kretschmer and the name on his parent's home was Kretschmer.

Investigator Siegfried Mahler said authorities had learned that the suspect was treated for depression in 2008, but had no further details.

Despite the high death toll, the shooting could have been worse if the principal of the high school had not been able to warn teachers with a prearranged code over the public address system when the suspect burst into the school.

After the suspect entered the school in Winnenden on Wednesday morning and opened fire, the principal put the emergency plan in effect, quickly broadcasting a coded message to teachers: "Frau Koma is coming," students told German media.

"Then our teacher closed the door and said we should close the windows and sit on the floor," a student, identified only as Kim S., told ZDF television.

In German the word "amoklauf" is used to describe school shootings, and "koma" is the reverse of the word "amok." Hetger said the coded alert was worked out by German educators after a deadly school shooting in Erfurt in 2002 as a way to warn teachers.

Hetger said that police in Baden-Wuerttemburg had received special training that involved sending small teams into the building in the event of a school shooting, as happened on Wednesday. He credited this, coupled with the warning from the principal, for preventing further deaths.

Questions:

1. How old was the youth who went on a killing spree in Germany?

2. How many fatalities were recorded, including the offender who took his own life?

3. At what time did the shootings take place?

Answers:

1. 17.

2. 16.

3. 9:30 am Wednesday.