The initial dismissal of the charge of rape by the chief prosecutor Eva Finné
After charges was made against Assange to the police on friday 20th august Maria Häljebo Kjellstrand, the Stockholm prosecutor decided that Julian Assange should be arrested on suspicion of rape and assault. The charges were: "Våldtäkt", i.e. rape and "Ofredande", which is a very broad term for anything from reckless behavior to stone throwing or shooting. Maximum sentence for ofrendande is 1 year in prison.
The decision was based on information given to the prosecutor on the phone by the police. Detailed information was not shared initially - this is according to laws about secrecy in cases of rape where there is a need to protect the involved from harm.
The decision was also influenced by the apparent fact that the accused was about to leave the country before being questioned by authorities.
Friday evening information about the arrest in absentia had reached a Swedish newspaper. They then got confirmation that Assange was the accused from the prosecution after detailing their information to the prosecution office.
When it was clear that this was a high profile case with worldwide media attention the case was refereed to chief prosecutor Eva Finné for a pre-trial investigation. Mrs. Finné started to look into the case immediately and around 16:30 on saturday she decided to lift the arrest order on Assange as she determined that he could not be suspected of rape. The basis for this determination was information that had not been available to the initial prosecutor. Precisely what that information was is not revealed by the prosecution.
The accusation of "ofredande" was not at that point dismissed.
Link to homepage of the swedish prosecution authorities:
http://www.aklagare.se/Media/Nyheter/Assangearendet-kronologi1/Then on 18 nov. prosecutor Marinanne Ny issued another arrest order in absentia. The reason for this was the need to interrogate him about the accusations of rape, sexual assault (ofredande) and illegal force.
Since then the defending lawyer for Julian Assange, Björn Hurtig have asked the swedish police to interview two witnesses, who have seen parts of the encounter between Assange and the two accusing women "up close". Their statements are expected to be detrimental to the credibility of the charges made by the two women.
Motive: hinder Assange being wikileaks legal responsible editor
So why would anyone make false accusations against the information activist? Beside the obvious reason - damage control in the PR-nightmare the disclosed documents has turned out to be - there is a subtle and perhaps more urgent reason: In order to become "legally responsible editor" of the swedish hosted Wikileaks website Assange would have to obtain a permit of stay and work for Sweden. A pending rape or sexual assault will at least post phone the issuing this permit.
The permit was applied for on 18. Oct. two days before the accusations of rape.
http://www.expressen.se/nyheter/1.2117156/assange-soker-uppehallstillstandMotive: DNA profiling of Assange
There is an additional motive for a false accusation: A DNA profiling of Assange would be useful for further surveillance of him or even further accusations.
http://www.expressen.se/1.2236153Multiple benefits
The choice of (false) rape accusations has a number of benefits for the accuser: Beyond the obvious - that there is very little obvious difference between consensual sex and what constitutes rape in a legal sense and the relevance of DNA profiling - there is the added bonus of extra "protection" of the accuser. Another added bonus is the smear factor for a large subset of the population of just having sex outside marriage. In essence a false rape accusation can be fun to prepare the setup for, offer extra protection for the accuser and have multiple benefits even when it fails in an actual trial. In this particular case there is also the added bonus of Assange being portrayed as being "on the run" while just going on his own business in the UK.