The sex assault case against two Ross River brothers collapsed on the second day of trial Tuesday, when the woman who pressed the charges ran from the courtroom and refused to return.

"You never know how a complainant is going to react until they get on the stand,” visiting prosecutor Robert Beck said outside the courtroom. "Obviously, seeing the accused can be very upsetting.”

Up to 80 per cent of sexual assault and domestic assault cases fall apart at some point in the proceedings, the Edmonton prosecutor said, usually because the complainant does not want to continue.

In the case, the woman began answering Beck's questions about her relationship with the two men, but left the stand when the questions started to delve into her sexual history.

"Let them walk,” she said, before removing her microphone and walking out of the courtroom. "Let them walk; just don't let them bother my family.”

Two hours later, the woman, whose name is banned from publication, got her wish, in the form of a one-year peace bond, which bars William and Phillip Atkinson from contacting the woman or her family.

She did not appear in court again, and Beck told the judge she could not be found and was not expected to return.

The two men, aged 59 and 53, were charged with aggravated sexual assault and unlawful confinement on Oct. 23, 2009, the day the woman told the RCMP and a Ross River nurse she had been raped the night before.

Those charges have now been dropped, and the two are free after spending a year in jail waiting for the trial.

It was a dramatic, though anticlimactic end to a case which has been kept tightly controlled by the court.

Last week, all members of the public were excluded from the court while lawyers argued over whether the defence team could ask the woman about her sexual history.

Normally in sexual assault cases, the woman is protected from such questions, but in this case, the judge said he would permit some specific questions. The woman left the stand before the defence lawyers had a chance to cross-examine her.

Then yesterday, the defence team tried to have the two men's statements to the police excluded on the basis they were strong-armed by the interviewing officer.

The judge decided to permit the statements, but the case collapsed before they could be entered into the court record.

William Atkinson is still facing charges relating to the case, however.

He is accused of making a threatening phone call last March to the woman's sister, who was supposed to testify at the trial.

He was subsequently charged with obstructing justice and uttering threats.

He will appear in court on Thursday in relation to those charges.