It has been a week when the internet has given us a unique window into the grisly and macabre.

Web users searching for information on the high school massacre in southern Finland can find a variety of documents and pictures purportedly written by the killer hours before the attacks took place.

A profile page linked to a video that anticipated the attacks is littered with rants and theories including the assertion: “It's time to put NATURAL SELECTION & SURVIVAL OF THE FITTEST back on tracks!”

His ramblings on the worthlessness of human life were being closely examined by thousands of curious internet users this evening in the belief that the killer had attempted to leave a message justifying his actions.

A similar trawl took place this week as the media searched for incriminating details of suspects in the murder of Meredith Kercher, the British student killed found dead in Perugia, Italy.

Photographs posted on social networking sites by suspects themselves were seized upon and printed in newspapers. A picture from Raffaele Sollecito’s weblog showing him posing with a meat cleaver was published, and Amanda Knox has been shown laughing as she plays with a machine gun.

Publicity hungry criminals have knowingly used this access to the media to promote their motives and desires.

Soon after the death of 11-year-old Rhys Jones in August videos made by the gangs thought to be responsible began to emerge on YouTube.

Numerous videos appeared showing the Croxteth Crew and their fierce rivals the Strand Gang showing off their dogs, weapons and shouting menacingly at the camera.

Media and police interest focused on the video-sharing site to such an extent that members of the public used the forum to name the teenager they thought was responsible for the killing.

The gangs had chosen to use the internet to advertise their hostility rather than confess to a crime, but they succeeded in generating a wealth of publicity.

The boys responsible for the Columbine High School massacre began the modern trend of videoing the first take of their own posthumous history.

When they filmed a chilling prediction of their school shooting in 1999, they were forced to rely on more traditional means of broadcast as social networking sites were yet to become commonplace.

Eric Harris and Dylan Klebold made a series of videos before they embarked on the shooting rampage that left 13 dead at their school in Colorado.

Their intention was to secure their place in history. In the films they claimed they wanted to inspire others to follow their lead believing they would "kickstart a revolution". They thought their home videos would inspire filmmakers to chart their story. In one of the videos, Klebold said: "Directors will be fighting over this story."

Officials initially attempted to keep the videos secret. Steve Jensen, the Jefferson County deputy district attorney, said at the time: "It's obvious that these guys wanted to become cult heroes of some kind.

"Dissemination of this material might allow Klebold and Harris to accomplish their goal, and we don't want them to appear to achieve that kind of status."

When Cho Seung Hui carried out the Virginia Tech college shooting in the US in April he did not give the police any chance to moderate his message. He sent a multimedia package of pictures, video and essays directly to the broadcasting network NBC.

In a terrifying set of videos completed after he had begun his murderous rampage he explained that the decadence of 21st Century America was responsible for his attack that left 32 dead.

The television network played the video in which he said: "You had everything you wanted. Your Mercedes wasn't enough, you brats. Your golden necklaces weren't enough, you snobs. Your trust fund wasn't enough. Your vodka and cognac wasn't enough."

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