Police have dropped an investigation into alleged racist comments made by a former Ukip regional chairman on Facebook.
Chris Pain was alleged to have described "illegal immigrants" as "sandal-wearing, bomb-making, camel-riding, goat-f******, ragheads".
Lincolnshire Police said it had investigated the allegations and that no further action would be taken against the Lincolnshire councillor or the other members.
Pain, who had blamed the remarks on a hacker, stepped down from his role as East Midlands regional chairman of Ukip as a "gesture of goodwill" following the allegations earlier this year. He remains leader of the party on Lincolnshire County Council.
In a statement, Lincolnshire Police said: "Police are reliant on there being a sufficient amount of evidence, of a quality which would support a decision to prosecute anyone suspected of carrying out crimes of this nature.
"When dealing with internet-based activity there has to be an audit trail which enables us to prove the person who is suspected of displaying information on the web is actually the person pressing the computer keys.
"There are many factors which make such an investigation very complex. Officers must work with the powers granted under specific legislation and, where the servers and the administration of the sites falls outside the United Kingdom, the Police and other enforcement agencies are often unable to obtain the relevant information needed to prove who placed comments or information on one of the sites. This is particularly the case with the main social media sites, such as Twitter and Facebook.
"In the world of increasingly technical equipment and expertise, it is always possible for false profiles to be created and information to be posted on a user's account without their knowledge. In such cases, it is very difficult for Police to trace the origins of the information and to be sufficiently certain that the person alleged to be displaying some comment or information actually did so."
Detective Inspector Andy Wardell said: "This problem is exacerbated when the social network account is closed by an individual who has either become aware or is directly made aware by someone that comments have been seen and the informant is going to contact the Police.
"Fictional Police and CSI shows often depict investigations where information in cyber space can be traced instantly but the reality is very different.
"Therefore, if any person discovers information displayed or comments posted to social networking sites which they feel are racist, or made with the intent of stirring up racism, they should inform the police immediately and not post responses or enter into dialogue with the individual believed to have made such racist comments.
"Doing so will inevitable result in the comments being removed and the account closed making it impossible to achieve a satisfactory result with any investigation".