A man accused of killing Jo Cox repeatedly visited neo-Nazi and white supremacy websites before allegedly killing the MP, the Old Bailey heard on Monday.
Thomas Mair also used the internet to search neo-Nazi websites and put together a dossier on the Labour MP, the court was told.
The jury was told that police found books inside Mair's home, including ones on German military history, the Holocaust and on Nazi SS race theory.
Another book was entitled March Of The Titans: A History Of The White Race.
Police also found a press cutting on Norwegian mass killer Anders Breivik.
A printout of a Wikipedia entry on the White Patriot Party was found in Mair's drawers along with information on the BBB - a notorious South African neo-Nazi organisation known as the White Liberation Movement.
Mair had allegedly collected a dossier on Mrs Cox in his home, including newspaper stories about her and a printout of her biography from her website, jurors were told.
Katy Green, Mair's neighbour, gave evidence via video link, describing the alleged killer as "very quiet, very shy" man who "did not see any visitors".
The court heard that in the months before he allegedly killed Mrs Cox, Mair repeatedly visited neo-Nazi, right-wing and white supremacy websites.
Prosecuting, Richard Whittam QC said Mair used computers at public libraries in Birstall and Batley to access the material.
After seizing eight computers, police examined Mair's internet searches.
The court heard that on 6 April he looked at the American neo-Nazi news and commentary site Daily Stormer, before searching for Dylann Roof, who is awaiting trial over the killing of nine black Americans at a church service in Charleston in 2015.
Others included searches relating to the Ku Klux Klan and to people who were murdered because of their civil rights work.
Jurors were also shown a YouTube video that Mair watched on 7 June of an American man shooting a 0.22 sawn-off rifle in a field, filmed on a head-cam.
This was the same day he searched for Mrs Cox on Wikipedia and Google images, the court heard.
Mair denies Mrs Cox's murder, possession of a firearm with intent to commit an indictable offence and possession of an offensive weapon - a dagger.