I remember, shortly after I became Muslim, a group of activists who I think were associated with a group then called “Al Muhajirun” sent a mass email to various clergymen, telling them to embrace Islam or face the consequences.
Amongst the recipients was my father who at the time was a Canon in the Church of England, whose email address they had harvested from a church website. The email was signed, in petition fashion, by a vast array of Muslim organisations, as if to give it authority. Of course, it turned out that none of the those organisations in fact existed and had been completely made up.
Therefore it does not surprise me in the slightest that other Muslim activists make up lawyers and send out threatening letters in their name to silence people, pretending to have some legal clout. I can believe it absolutely. It’s a long time since I believed that Muslims, generally speaking, are a people of truth. The behaviour of too many activist Muslims is risible.