A Falmer For All campaigner is facing prosecution over posters that criticise Lewes District Council leader Ann de Vecchi.
Photographer Roz South has been told by police she is being investigated following a formal complaint of harassment by the council.
Ms South has refused a request by Inspector Viv Johnson to remove a poster from her website, which she produced on behalf of the Falmer For All campaign.
The poster depicts Councillor De Vecchi above the words: "Wanted, for attempted murder of Brighton and Hove Albion Football Club."
The poster was widely circulated among Albion fans in December. It was part of a campaign to persuade the authority not to pursue a High Court challenge against Deputy Prime Minister John Prescott's decision to grant the Falmer stadium planning permission.
Ms South, of Firle, near Lewes, said: "As far as I am concerned, the poster amounts to legitimate political protest, which Lewes District Council is attempting to silence by using police resources, and I am not inclined to remove it as a matter of principle."
In an email to Ms South, Insp Johnson said: "I have contacted the Crown Prosecution Service (CPS) as to whether an offence contrary to the Protection from Harassment Act has been committed.
"The advice is that there may be a case to answer and I shall take further advice before pursuing my investigation."
Ms South has been warned she may be pulled in for questioning over the poster, which she published on her website at www.allthingsbrightonbeautiful.com Ms South said: "At best I consider the council to be oversensitive about an extremely contentious issue and at worst, I think they are inappropriately using the police to suppress opinions.
"At no point has Lewes District Council approached me about this poster and I'm rather surprised at the timing of the complaint since the image itself was prepared at least ten weeks ago "I recognise that there is emotive language used in the poster but this is a reflection of a very widely held view that ever since Liberal Democrat MP David Bellotti was involved in the sale of the Goldstone ground, local Liberal Democrats have been trying to kill off the Albion.
"As far as I'm aware it is still not illegal to lampoon politicians, although I recognise they don't always take kindly to it.
"There is something wrong in the world if the CPS thinks I should be prosecuted for a poster days after it decided to take no action against Ann de Vecchi's partner, David Freeman, who was accused of assaulting an Argus photographer.
"If I am arrested I will not accept a police caution."
A spokeswoman for the council refused to say whether or not the complaint had come from an individual councillor or the authority as a whole.
She added: "This is a police matter and we have no comment to make."
Coun De Vecchi told The Argus she had not made the complaint to the police and she did not wish to comment.
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