Some of the letters have featured similar cartoons
Police said they have received 86 calls after appealing for help to catch the culprit behind a hate mail campaign.
Dozens of people across the UK, including the prime minister, have been targeted by the writer - who police believe could be an older woman.
Since January 2007, 57 racially and sexually abusive letters have been sent to mosques, hospitals and universities.
The BBC's Crimewatch show generated 36 calls on Tuesday while 50 calls were made to Hampshire police.
Gordon Brown's Fife constituency office was sent a letter in April, with the most recent delivered to a private address in Havant, Hampshire, in July 2009.
They have also been received in Derbyshire, Merseyside, Lincolnshire and Bedfordshire.
Much of the hate mail, most postmarked Portsmouth and the Isle of Wight, includes references to "repatriation" and "exit Europe".
Officers revealed on Crimewatch they believe a woman is involved in the letters following forensic tests.
They appear to be claiming to be older, they are writing about pensions, people who have worked for 50 years or more of their life.
Dr Tim Grant, linguistics expert
Dr Tim Grant, a linguistics expert, said: "The assumption can be that these sorts of letters are written by a man.
"But we have run some analysis which would support the idea that it might be a female.
"It is to do with the language they use, a heavier use of adjectives, in particular words like 'smelly' and 'filthy'.
"They appear to be claiming to be older, they are writing about pensions, people who have worked for 50 years or more of their life.
"They are also using older terms of abuse."
Det Insp Donna Goff, of Hampshire Constabulary, said the appeal had generated a "great response".
"A lot of interesting information has come in to us and there is a great amount of work to be done in the next few days to go through this and see if anything can help us establish the identity of the letter writer," she added.