a person who spreads stories deliberately to make people frightened or nervous
rumour-monger / gloom-monger / doom-monger etc, someone who says unpleasant things
传播谣言的人/散布悲观论调的人等:
The rumour-mongers have been busy again.
好造谣的人又在忙了。
the economic gloom-mongers
散布经济悲观论的人