World Mar. 14, 2009 - 07:00AM JST ( 4 )

WINNENDEN, Germany —

The number of people grilled by police over hoax Internet warnings of school shootings across Europe rose to four on Friday, two days after a teenager shot dead 15 people in Germany.

The latest hoaxes came after it was separately revealed that the perpetrator of Wednesday’s bloodbath, Tim Kretschmer, had probably not given an Internet warning—contrary to what investigators had previously been led to believe.

Those behind the message that officials initially believed was a chilling warning by Kretschmer—citing weapons and intent to go to his old school in Winnenden—have yet to be discovered.

German police in Lower Saxony, hundreds of kilometers from the scene of Wednesday’s rampage, said they arrested a 21-year-old man after he boasted in a chat room that he would carry out a similar crime.

“I have a gun and I’m going to kill everybody,” read the message. The man, who has not been named and who faces up to three years in jail or a fine, said that it was meant “as a joke.”

French police dealt with a similar scare, arresting at 6 a.m. an 18-year-old youth after he too posted a “joke” website warning of a shooting spree at a school in the Paris suburbs.

“In Raincy (high school) there will be blood—I have weapons,” this message read.

In the Netherlands, an 18-year-old man was arrested at 4 a.m. in Rijsbergen for a similar warning posted on a U.S. website, police sources said.

The teen was arrested at home after having been traced through the IP address of his computer, said a police statement. He admitted to being the author.

And Swedish police took in for questioning a 17-year-old suspected of posting a picture of himself posing with a weapon on an Internet forum, along with a threatening message against a high school.

On Friday, a school at Ilsfed, near the scene of Wednesday’s killing, was cordoned off and searched by police after another Internet threat, but it turned out to be a false alert, local police spokesman Roberto Monaci said.

Dressed in black combat gear and armed with a gun taken from his father’s bedroom, Kretschmer shot dead eight girls, one boy and three female teachers at his old school.

He then killed a passer-by outside a psychiatric clinic where he had been due to receive treatment, hijacked a car and shot two others at a car dealership.

By this time hundreds of armed commandos were on his trail, some in helicopters, and Kretschmer died in a shootout with police around 30 kilometers from the school. Police believe he shot himself.

The interior minister of the state where this took place said on Friday that the 17-year-old—described as unremarkable and reserved if socially awkward and suffering from depression—had announced his intentions on the Internet.

But on Friday the minister, Heribert Rech, admitted that he had been duped.

“Some crazy person obviously put out this dreadful false message,” Rech said. “It must have been made up afterwards.”

After analyzing Kretschmer’s computer, on which he had spent hours playing “shoot-em-up” video games, a spokesman for local police said no trace had been found of the message.

The picturesque town near Stuttgart was still in a state of shock on Friday, with people laying flowers and candles outside the Albertville secondary school, which remained closed.

Chancellor Angela Merkel will attend a memorial service on March 21 in the town, her spokesman said on Friday.

Two policemen injured in Wednesday’s car park shootout were still in hospital, as were five pupils from the school, police said. Some the pupils had gunshot wounds and others had broken bones after jumping out of windows.

Wire reports