Threatening letters

(Law) letters containing threats, especially those designed to extort money, or to obtain other property, by menaces; blackmailing letters.

See also: Threatening

References in classic literature ?
Seized with an indescribable fury, they addressed threatening letters to the different members of the Gun Club by name.
Five times in the last fortnight he's had threatening letters left at my flat, and I can't even find out who leaves them, let alone if it is Welkin himself.
Yes," replied Smythe coolly; "they can't tell me who left those threatening letters at my flat.
Nobody writes threatening letters about money to this place.
Perhaps he connected it in his own mind with one or two outstanding accounts, in reference to which he had already received divers threatening letters.
On the very top of Sir Isaac's papers," explained Harker, "there was a threatening letter from a man named Hugo.
A WOMAN who admitted harassing her sex offender neighbour with threatening letters has received a 12-month community order.
Toskas said that sending threatening letters to those who have been trying to settle a problem in a honest manner was "dangerous".
Euzoy-uz, the first woman with Turkish roots to become a German minister of state, has revealed that she has received hateful emails and threatening letters.
Sciesniewski of Southbridge to six months of pretrial probation in a case stemming from threatening letters he sent in September to state Sen.
We have shared Taliban's threatening letters with government but no measures are being taken for ensuring our security," he deplored.
WASHINGTON, May 20 (KUNA) -- A man who pleaded guilty to developing and possessing ricin and sending threatening letters to US President Barack Obama and other officials was handed a 300-month prison sentence.