The alleged gunman is believed to have uploaded videos and 'manifesto' documents to a website which "point to deeply racist views".
German prosecutors are investigating the online profile and activity of the alleged gunman who killed nine people at hookah lounges in Hanau on Wednesday.
Police say the 43-year-old suspect was later found dead at his home, alongside another body of a female relative.
The interior minister for the state of Hesse, Peter Beuth, said a website believed to be the suspect's indicated "a xenophobic motivation".
Federal Prosecutor, Peter Frank, added that the alleged gunman had uploaded "video messages and a kind of manifesto".
"In addition to obscure thoughts and absurd conspiracy theories, [these] pointed to deeply racist views".
The video uploaded to YouTube
One of the videos first appeared on the popular video-sharing platform YouTube on February 14.
It shows a man sitting in a room, speaking directly to the camera and expressing conspiracy theories.
The account was terminated by YouTube on Thursday morning, several hours after the shootings were first reported.
YouTube told Euronews that they did not consider the original upload to be a 'manifesto' video, and it did not directly violate any policy.
But the social network said that the account was removed as soon as they were made aware of the connection to the shootings in Hanau.
This was said to be in line with YouTube's code of conduct, especially given the horrific nature of the shootings.
Euronews understands that videos which contain copied or hashed content of the original upload will continue to be removed from the platform.
YouTube added that their systems for flagging content had worked as intended and that their response protocols had been effective.
But the social media giant did acknowledge the challenges they faced and said they were working hard to remove hateful, violative content, linked to the shootings.
Versions of the video appeared elsewhere across social media on Thursday, in both online chat rooms and more mainstream platforms, such as Twitter.
Twitter told Euronews that they were taking action against the content, under their policy against the Glorification of Violence and were continuing to monitor the situation on their service.
Versions of the video could still be found across the Internet on Thursday evening.
The International Centre for the Study of Radicalisation and Political Violence said that they had found another video linked to the suspect, which contained "far-right narratives" and "more surreal and less tangible conspiracy theories".
Director Peter Neumann tweeted that the videos and manifesto seemed to indicate a "significant mental health issue".
Peter Neumann added that the suspect behind the manifesto did not seem to represent a user of "chan" websites.
Online message forums '8Chan' and 'EndChan' have been linked to previous mass shootings in New Zealand and the United States, as well as an attempted shooting in Norway in August.
Germany seeks to extend laws on online hate
Germany has sought to increase pressure on social media companies in relation to online hate speech, following a number of acts of violence in the country, linked to far-right extremism.
The shootings in Hanau occurred just days after 12 people, who were communicating in chat groups, were arrested for planning an act of "right-wing" terrorism.
Meanwhile, in October, two people were killed in the city of Halle in an 'anti-Semitic' attack, which was live-streamed on Amazon’s Twitch service.
On Wednesday, the German ministers approved a bill that extended their laws on online hate speech.
The new measures would require social networks to report harmful content, including far-right propaganda, to the police.
The Federal Cabinet said the draft laws would combat right-wing extremism and hate crime.
Bundestag member Katja Leikert, who represents the Hanau district, said Germany "must show determination to defend our liberal democracy".
"There is no doubt that we are using all the means available under the rule of law to combat hatred, right-wing extremism and xenophobia".