A jury has been unable to reach verdicts in the trial of a former Australian National University doctorate candidate who is accused of raping a woman during a picnic.
The man, who cannot be named in order to protect the identity of the alleged victim, had faced a two week ACT Supreme Court trial.
On Wednesday, Chief Justice Lucy McCallum dismissed the jury after three-and-a-half days of deliberations when they were unable to reach a unanimous verdict.
"You have been a particularly hard-working, easy-going, appearing-to-treat-others-respectfully, group of people," the Chief Justice told jurors.
"A person should not be acquitted or found guilty unless 12 people agree."
The former ANU PhD student, 36, has pleaded not guilty to two counts of sexual intercourse without consent.
The case is next set to go before a registrar in four weeks, but it is unknown at this stage if there will be a retrial.
In his closing address to jurors last week, prosecutor Trent Hickey said the alleged victim described the relationship as "love-bombing" with about 3200 messages between the pair sent over several weeks.
Mr Hickey said one of these messages included the accused man saying he "preferred his partners to be into BDSM".
The alleged victim was said to have told him it made her "uncomfortable", but she wanted to please him so she "played along".
"The accused was sexually dominant, sexually assertive, in the relationship," Mr Hickey said.
The woman "felt trapped by his behaviour", the prosecutor previously told jurors.
Mr Hickey said the prosecution case was that the man raped the woman two different ways while they were having a picnic along the Cotter River to celebrate his birthday.
After the alleged rape, the 36-year-old is said to have told the woman he would shoot or stab her if she became "a liability".
Over the two-week trial, a second woman gave evidence claiming the man had sexually assaulted her, but he has not been charged in relation to the allegation. The prosecution used this evidence to allege a pattern of behaviour.
In his closing address, defence lawyer Andrew Tiedt told the jury the sexual acts involving the first alleged victim were consensual and there was "not a skerrick of independent evidence" about the alleged threat.
"[The woman] freely and voluntarily consented to what occurred," Mr Tiedt said.
- Support is available for those who may be distressed. Phone Lifeline 13 11 14; 1800 RESPECT 1800 737 732; Canberra Rape Crisis Centre 6247 2525.