HALIFAX -- A young woman hurriedly left a courtroom Friday after a judge questioned her credibility and acquitted a British sailor accused in an alleged gang rape at a Halifax-area military base.

Darren Smalley was charged with sexual assault causing bodily harm and participating in a sexual assault involving one or more people in barracks at 12 Wing Shearwater on April 10, 2015.

But Justice Patrick Duncan said he did not believe portions of the complainant's testimony and concluded the charges had not been proven beyond a reasonable doubt.

"It is my impression that the complainant was selective in how she presented her evidence of her conduct throughout the evening," Duncan said in Nova Scotia Supreme Court.

"She maximized that evidence which supported her narrative and minimized any events that might be inconsistent with her narrative."

Smalley, who is in his late-30s, showed no emotion after the verdict, while the young woman, who is in her mid-20s, wore a stern stare as she left with a group of supporters.

Outside of the courtroom, Smalley told reporters he was relieved.

"It's been four years of my life," said Smalley, wearing a grey suit and speaking quickly. "It's took a toll on me mentally and physically."

Ian Hutchison, Smalley's lawyer, said his client will now return to the United Kingdom and will be "moving on with his life."

"It's a very difficult day for him, it's a very emotional day. It's a difficult day for all the parties before the court this morning," said Hutchison.

The woman and a friend had met the men, members of a Royal Navy hockey team in Halifax for a tournament, through Tinder.

The complainant testified at Smalley's trial last fall that she fell unconscious while lying in bed next to a sailor, and later awoke face down and naked as at least three men sexually assaulted her.

Duncan said the complainant's testimony was inconsistent with the accounts of other witnesses who were inside the barracks that evening.

He said he did not accept her testimony that she lost consciousness, noting that she had not consumed enough alcohol or other substances to be impaired, nor was there any medical evidence to explain why she lost consciousness.

Duncan said her friend testified that when she came into the room after the alleged assault, the complainant expressed concerned that compromising photos were taken of her. He said that evidence indicated the complainant was fully alert at that time, and contradicted her testimony.

"It's impossible to know where the truth begins and ends in this matter," said Duncan, adding that he found the complainant's friend to be a more credible witness.

"Obviously something of a sexual nature occurred in that room. Maybe it was a criminal offence, maybe it was not. But without credible evidence, it is unsafe to convict."

Duncan said the complainant is intelligent and well-spoken, but characterized her testimony as "controlled."

"The degree to which she prepared herself as a complainant from the outset has undoubtedly influenced the manner in which she presented her evidence," he said.

"If demeanour was the only gauge of truthfulness of her testimony, than she would be viewed as highly credible, however demeanour is a notoriously poor gauge of truthfulness or reliability."

Prosecutor Eric Taylor said the Crown disagrees with Duncan that the complainant's testimony was not credible. He acknowledged the woman's loss of consciousness and the difficulty explaining it was a challenge for the prosecution.

"The credibility was the central factor in this case," said Taylor outside of court. "We felt the inconsistencies were minor and that the complainant's credibility was clear throughout, but the court found differently."

Smalley did not testify at the judge-only trial.

Four men had originally been charged, but charges were dropped against two of them before trial, while another man's case was stayed after he became ill.

Taylor said the Crown will make a decision on whether to reinstitute the charges against one accused, Simon Radford, before the expiry of the stay of proceedings this October, and Smalley's acquittal may impact that decision.