South Yorkshire Police confirmed yesterday that the force have received three reports of people in the county receiving the vile letter, which encourages people to take part in a 'punish a Muslim' points-scoring game.
Counter Terrorism Policing North East is coordinating the investigation, and Detective Chief Superintendent Martin Snowden, Head of Counter Terrorism Policing North East today condemned the letters.
He said: "We take religious hatred extremely seriously and my officers will be carrying out a full and thorough investigation in response to these reports.
"These letters seek to cause fear and offence among our Muslim communities. They also seek to divide us. Yet in spite of this our communities have shown strength in their response to such hatred and in their support for each other.
"We continue to encourage anyone who believes they have been a victim of such an offence to contact their local police force on 101. We'd also appeal to anyone with any information about the individual, or individuals, responsible to call police in confidence on 0800 789 321."
The Sheffield and Balby Quakers' group have also condemned the letter.
A spokesman said: "Sheffield and Balby Quaker Meeting met on Sunday 11th March and expressed their deep sorrow and outrage on hearing of the letter circulated by person or persons motivated by hate.
"Entitled 'Punish a Muslim day,' the letter urges an escalating series of “punishments”.
"We Quakers wish to offer a hand of friendship and solidarity to all Muslim communities and invite people of all faiths and none to stand with them against racism and hatred."
In addition to letters being received in South Yorkshire, it is suggested that at least one of the hateful letters was sent from Sheffield.
One of the six people in West Yorkshire to receive the letter, Councillor Riaz Ahmed, a Liberal Democrat councillor in Bradford, told The Mirror: "It was not addressed to anyone, just the address and postcode as if it was sent out randomly. It has a second class stamp on the plain white envelope and the frank mark is Sheffield. It was posted yesterday.
"It seems strange that anyone would send something like this to an address in a predominantly Muslim area. When I opened it and saw the content I was horrified."
Anyone with information is asked to call South Yorkshire Police on 101, quoting incident number 420 of March 11, 2018.