A teenager was looking at videos of mass murders edited in the style of the Hollywood film The Matrix, a court has heard.
Jurors at Gloucester Crown Court were shown videos depicting glorified versions of the Columbine massacre and heard defendant Kyle Davies had visited online forums debating the killings.
The court was also told he had searched for instructions on making explosives.
Mr Davies, 18, from Gloucester, denies weapons and ammunition charges.
Det Sgt Daniel Bickford of Avon and Somerset Police told the court he had gone through the search history on Mr Davies’ laptop.
Several searches were made between 8 March and 18 April 2018 about the Columbine massacre and he also tried to find the journals of the two killers, Eric Harris and Dylan Klebold, jurors were told.
Police also found a book at Mr Davies’ home relating to the psychology of the Columbine killers.
Jurors were told other searches were made about Anders Brevik, who murdered 69 people in Norway in 2011.
The court had previously heard UK police were alerted when a package addressed to Mr Davies containing a gun and bullets was found at a US airport.
Mr Davies, of Wotton, denies two counts of attempting to possess a Glock 17 pistol and five rounds of 9mm ammunition with intent to endanger life.
The trial continues.