IN the months leading up to the arrest of two teenagers by the North East Counter Terrorism Unit, the older boy obsessively pursued his interest with the Columbine killers and both boys carried out dozens of internet searches for information on bomb-making and school shootings. Here is a timeline of events leading up to their arrest and being charged

MARCH 3 Older teen uploads a video glorifying the Columbine shooters onto his YouTube account, which included CCTV footage from inside the school at the time of the attack.

MARCH 10-31 Older teen carries out an internet search on school shootings and Nazism.

APRIL 1-6 Older teen carries out internet searches for balaclavas.

APRIL 25 Older teen sets up Instagram account mocking a teacher at his school. He superimposes her head on Nazi images, and posts offensive and abusive comments about her. School excludes older teen for several days and notifies police, who issue him with a Community Restorative Disposal Order.

MAY 2 Older teen searches for information on the Columbine killers and information on “Natural Selection”, a slogan worn on a T-shirt by Eric Harris during the massacre and later found on a T-shirt in the older teen's house. He also searches out anti-Semitic content on YouTube.

MAY 5 Both teens download a bomb-making manual.

MAY 6-15 Older teen continues searching for information on explosives, guns, bomb-making, Nazis and ammunition. Younger teen shares information from the bomb-making manual with the older teen. Older teen sets up a second fake Instagram account, posting offensive images involving the Ku Klux Klan, Nazism and Auschwitz.

Younger teen uploads a video of him blowing up an aerosol can to YouTube. The two defendants exchange information on school shootings. Younger teen messages the other defendant, telling him: “I can’t be bothered any more”. Older teen tells him: “If you’re going to kill yourself, shoot up the school."

MAY 18-22 Older teen continues searches for information on incendiaries and explosives and school shootings and extreme violence. 

MAY 25-27 Older teen is excluded from school for several more days. He continues internet searches on death videos and killings.

JUNE 4 Older teen uploads another video on Columbine to his YouTube account, begins researching how to buy guns and accessing the dark web.

JUNE 24 Older teen meets with his girlfriend for the first time after meeting over Instagram via a mutual friend.

JUNE 26 Older teen uploads another video on Columbine including footage from inside the school.

JULY 13-AUGUST 26 Older teen continues researching notorious murderers and the Columbine massacre and posts a picture of them on Instagram with the words, “They only murdered 13 people, only 13.” He also adds another video on Columbine to YouTube and a video of an American white supremacist.

AUGUST 17 Older teen’s girlfriend messages him to tell him she has found the keys to her father’s gun cabinet, writing: “Guess which good girl found the keys?” The court later heard she made this up to “make him happy”.

SEPT 4 Older teen carves his name into his girlfriend’s lower back with a penknife in his hideout and he also later messages his girlfriend threatening to kill himself and harm and kill others. He texts his girlfriend: “I want to kill someone so badly right now. I need help baby.” He later carves his girlfriend’s name into his lower arm – spelling her name incorrectly – and sends her a picture.

SEPT 8 The two defendants send each other a text message, with the younger one stating: “I really want to shoot up the school and it would be, like, so much fun.” The older teenager accesses extremely violent content on the dark web and researches hacking computers. A complaint is made to the headteacher of the girl’s school about the conduct of her boyfriend towards her. His conduct is reported to police, but no formal police action taken.

SEPT 15–22 Older teen searches on the internet for combat equipment and clothing and computer hacking. Younger teen uses school computers to research school shootings. Older teen has the first of several sessions with North Yorkshire’s Child and Adolescent Mental Health Service (CAMHS).

SEPT 27 Younger teen messages his mother and asks her to buy him a trench coat. Younger boy also sends a list of names of staff and pupils they intend to kill to another friend and also sends it to the older teen.

SEPT 28 Younger teen encourages the older teen to wear his trench coat to school, saying he wants “everyone to be scared”. Younger teen confesses their plans to attack the school to a senior teacher, saying “only the guilty will die” and explaining he was doing it because the bullying in school was driving him to suicidal thoughts. North Yorkshire Police officers speak to two boys in their homes. The younger boy again confesses to police they were planning to kill students because the school bullying was unbearable. Older teen denies everything. Within minutes of police leaving, the teenager returns to his computer to continue researching Columbine and “teenagers arrested for plotting Columbine”. Neither boy is cautioned by police.

SEPT 29 Boys’ mobile phones are seized by police. After police have left, older teen searches on the internet for bomb-making information and instructions

OCT 11 Older teen writes in his diary of his plans to run away to Catterick Garrison and “lay low” for a while before murdering his ex-girlfriend’s parents, stealing her dad’s guns and then making explosives and heading back to Northallerton to “begin out assault on that f***ing school".

OCT 12 Older teen’s diary entry: “I’m finding contacts for weapons.”

OCT 14 Older teen places notes to his girlfriend in her bedroom window after they have been banned from seeing each other. Her parents find notes and Nazi graffiti on an outside wall of their home.

OCT 21 Older teen breaks into the home of his girlfriend through a bedroom window. When disturbed by her parents he flees and is seen running with a large knife.

OCT 22 Older teen’s hideout is searched in Catterick Garrison. Potential ingredients for bombs are discovered along with a balaclava.

OCT 23 Older teen is arrested by North Yorkshire Police for offences relating to his girlfriend and her family. North Yorkshire Police search older teen’s bedroom and seize his diary, Kindle and SIM card. His laptop was handed to police by his dad which had been in the boot of his car. 

OCT 28 Counter Terrorism Unit arrest both teenagers on suspicion of serious offences.

NOV 1 Both boys are charged with conspiracy to murder and the older teen is charged with aggravated burglary.

NOV 26 Knife with “love” written on it is found in Catterick Garrison by family out walking. It is identified as part of a set found at older teen’s home.