Rowaida Abdelaziz tweeted "'Punish A Muslim Day' letters are being sent to families in East London. The letter details a point system for each action & a reward. For example pulling a Muslim women's hijab is 25 points, throwing acid is 50 points and burning or bombing a mosque is a whole 1,000 points."
At first glance, the mailings didn't seem like much. They arrived in plain white envelopes, with second-class stamps.
The letters inside, though, were a different story. Big red and black letters declare April 3 "Punish a Muslim" day. Underneath, a ranting paragraph attacks Europe's lax immigration policies, along with Muslim immigrants.
"Are you a sheep like the vast majority of the population? Sheep follow orders and are easily led," it reads. "They are allowing the white-majority nations of Europe and North America to become overrun by those who would like nothing more than to do us harm and to turn our democracies into sharia-led police states."
Below, a chart offers "points" for offenses against Islam: pulling off a woman's headscarf would net 25; killing a Muslim, 500. Bombing a mosque would get you 1,000 points, and you'd receive 2,500 to "nuke Mecca."
"They have hurt you, they have made your loved ones suffer. They have caused you pain and heartache. What are you going to about it?" the anonymous missive asks.
According to authorities, at least six communities around the United Kingdom have received the letters, which are being investigated by the country's counterterrorism forces. Tell Mama, an organization that monitors anti-Muslim activity, has received reports of letters being received in Cardiff, Leicester, London and Sheffield.
TellMAMAUK tweeted "'Punish a Muslim Day' - we continue to receive reports of letters received from across the country. Now into double figures. Please report them into us at Tell MAMA or to 101. We are working with police forces on this malicious campaign."
"This has caused quite a lot of fear within the [Muslim] community," Iman Atta, the director of Tell Mama, told reporters this weekend. "They are asking if they are safe, if their children are safe to play outdoors. We have told them to keep calm."
In a Facebook post, Naz Shah, a member of Parliament, wrote that members of her community are very distressed. "I would appeal to the wider community to remain vigilant and report any suspicious activity to the police," she wrote.
It's not clear who sent the letters or what they're trying to accomplish. It seems, though, that the writers targeted predominantly Muslim communities. Politician Riaz Ahmed, for example, said he received one at his home in Bradford. The residents of his neighborhood are mostly British Pakistanis of Muslim backgrounds. "My guess is that the letter was meant to terrorize and cause discord within the various communities," he said in the New York Times.
According to a 2016 census, there are about 4.1 million Muslims in Britain, about 4.4 percent of the population. That population will likely triple in the next 30 years, according to Pew, thanks to migration. Muslim women also have, on average, more children. Even so, a 2016 study also found that Britons overestimate the number of Muslims in their country.
That's part of a broader trend - in the past several years, Britons' attitudes toward Muslims have worsened, with more than half of respondents from one survey saying that Islam poses a treat to the West. A quarter of respondents called Islam a dangerous religion.
Hate crimes, too, are on the rise. According to the country's Home Office, last year, hate crimes against Muslims jumped 29 percent, to 80,393 reported offenses. It's the biggest jump since the Home Office began keeping track in 2011. Those incidents included several arson attacks on mosques and a British man accused of ramming a van into a group of people leaving a mosque. One person was killed; seven others were injured.