POLICE say farmers have been targeted by "downright disgraceful" vexatious letters that have been hand-delivered to their properties.
Now, investigators believe more could have been sent and they're appealing for public help.
Police received the first report of an offensive letter from a property owner at Dubbo on November 19.
Officers then received reports a typed letter of a similar nature had been sent to a property owner at Walgett this week, as well as another by a property owner at Peak Hill.
Each of the letters refer to the current prolonged drought conditions and make suggestions to the victims that they should take the lives of themselves and their livestock.
Police said initial investigations indicate the letters are being hand-delivered to mailboxes.
Investigations are continuing into the letters, and police are urging victims to photograph and preserve the letters and envelopes before making a report to local police.
The state's top rural crime boss, Detective Inspector Cameron Whiteside, has labelled the letters as disturbing, adding unnecessary stress to landholders during an already difficult time.
"This is downright disgraceful," Detective Inspector Whiteside said.
"It is extremely important that these letters are not over-handled, both in a physical sense and by not disclosing information to fellow members of the public which may impact the investigation.
"Victims should report the matter to local police in a very timely manner in order to increase our chances of resolving the nature of these letters.
"Anyone who has received a similar letter is encouraged to contact their local police station and report the matter."