A man rides his bike slowly down Atlantic Avenue in Brooklyn, slows even more when he sees the entrance to a mosque and then shouts: "You're all gonna die!" in the full gaze of two New York police officers. Minutes later and only yards away, another man walks into an Islamic gift shop and says, for the second day running: "I'm gonna bomb you out!"
Such threats, which took place before my eyes, have become commonplace in Islamic communities since last Tuesday's calamities in New York, Washington and Pennsylvania. In the absence of the swift retribution they had hoped for, some of America's grieving people have taken to confronting the only "enemy" they recognise: Islamic Arabs who for so long have been demonised by the US media.
The mosque in question was, depending on whom you believe, a quiet place of worship in a peaceful Muslim community – or a recruitment centre for Mujaheddin rebels during the war against the Soviet Union in the 1980s. And, to spice things up, some believe that Osama bin Laden, the main suspect for last week's atrocities, set up the mosque himself.
The al-Farooq mosque has no ostentatious golden dome or ornate gates. Its entrance is hard to find and leads down a corridor not of gold leaf and marble, but of a kind of 1960s municipal drabness. In here, worshippers are talking of stabbings against women, threats to children and blind retribution against men. It is difficult to know how much is true. But one thing is certain; they are very frightened.
"I have heard of three women being stabbed because they were wearing traditional dress – their faces were covered," said Mosad Almontaser, a language and arts teacher in Brooklyn. "We have had kids intimidated at school and a lot of parents have stopped them going there for the time being. It is very sad because we consider ourselves American, but many Americans think all Muslims are terrorists and criminals. We are grieving too over what happened, but for us it is a double whammy: we feel sad, and we get the blame."
As if to illustrate the fear inside the mosque, on the wall outside is pasted a note of sympathy for the victims and their families, complete with a beginner's guide to Islam. It reads, sadly, like a disclaimer.
Quoting from Chaper 6, Verse 151 of the Koran, it says: "And kill not life that Allah has made sacred ..." It goes on: "On 11 September, a tragedy has occurred. The Muslim community is outraged by these senseless acts of violence. Our way of life, Islam (the way of peace), does not permit such unjust acts. Muslims are NOT terrorists. We condemn terrorist acts against Muslims or non-Muslims. May Allah give us patience in this time of distress and bring peace and security to the nation."
Several doors down, at the Al Haramain Islamic gift and cultural shop, Abdul Farhan, a 46-year-old native of Morocco, feels anything but secure. It was he who was threatened twice by a prospective "bomber", but his remonstrations with the police got him nowhere.
"I showed them who he was and what he had said, but they let him go – I even told them I had witnesses," he said. "First he threatened me and said all Muslims were going to Hell, and then he threatened me again, with a bombing. But we are not terrorists; we are peaceful people who just want to enjoy freedom in America to work hard and bring up our families. From the media, you would think we are all criminals."
A New York journalist, Michael Daly, has traced the mosque's history back to Mr bin Laden during the days when the United States was funding Afghanistan's fight against Soviet occupation. The mosque was, he says, set up by the Saudi cleric and then spawned a faction that opened the Alkifa Refugee Centre near by. This centre in turn fragmented because of in-fighting and murder.
Inside the mosque, senior muslims deny the claims. The imam, Abdul Rehman, said Mr bin Laden had nothing to do with the mosque and had never set foot in it. However, his knowledge of its history is questionable – he has been in post less than two weeks.
Another worshipper, Wisser Mountassir, 38, who said dozens of friends had given up jobs to avoid retribution, was a little more forthcoming. "There was a place in here where people used to come and volunteer to fight in Afghanistan," he said. "Of course, it was all with the knowledge of the Americans. They were trained here, and then sent over there to fight."
Some of the same Mujaheddin – and the shoulder-fired anti-aircraft missiles supplied by the US – are now likely to be the target for American military strikes. It is the sort of policy that has come back to haunt America more than once.
For a few moments, the mosque seemed a sad and crazy place to be. Then a young white mother, Providence Hogan, carried in her four-month-old daughter, Sophia, and a bunch of flowers. She handed them to the frightened young men awaiting prayer.
"I just wanted them to know that not all Americans see them as terrorists," she said. And the card on the bouquet restored a little sanity to the occasion. "Our enemy is a common one," it read. "Ignorance."