Letters encouraging recipients to take part in “Punish a Muslim Day” have reportedly been sent to addresses across the UK.
Inside was a message so hateful that it sent out ripples of alarm and prompted a national counterterrorism investigation.
Images of the A4 notes, which contain a list of violent acts alongside a number of points for performing them, have been widely shared online.
They have prompted a chorus of condemnation, with campaigners and MPs describing them as “disturbing”.
Counter-terrorism police are treating the letters as a possible hate crime.
A police spokesperson said: “Counter Terrorism Policing North East are co-ordinating the investigation at this time and will consider any potential links to existing inquiries.
Source: BBC