Unite has welcomed a police announcement that it has found no evidence of any criminality over a union official involved in a row over the selection of a Labour party candidate.
Stevie Deans left his job at the Grangemouth oil refinery in Scotland last year and decided not to seek re-election as chairman of Labour's constituency party in Falkirk.
Unite was accused of trying to sign up members to influence the selection of a Labour candidate in Falkirk, but always denied doing anything wrong.
Mr Deans was suspended by Grangemouth's owner, Ineos, over claims that he used company time for political campaigning work, but his treatment prompted a vote for strike action, which led to a temporary shutdown of the plant.
Mr Deans resigned from his job at Grangemouth and from his position as Unite convenor.
A number of emails were sent to the police.
A Police Scotland spokesman said: "Following information received alleging misconduct by a member of staff at the Grangemouth refinery, a Police Scotland inquiry was undertaken. This inquiry has now concluded and there is no evidence of any criminality."
Len McCluskey, Unite general secretary said: "Unite has been vindicated in consistently saying that no wrongdoing or criminality has taken place and welcome Police Scotland's conclusion.
"It is shameful that the police's time has been wasted by vexatious complaints and their attentions diverted from catching real criminals and solving real crimes.
"Stevie Deans is a decent and honourable man who has been smeared and hounded with a callous disregard for him and his family by those who should know better.
"The anti-union hysteria whipped up by certain sections of the media and their friends to pursue a spiteful agenda, has been shocking. Their witch-hunt has been exposed to be without foundation and a lie."