PICTOU, N.S. -- The jury at the Amber Kirwan murder trial began deliberations Monday after the judge presiding over the case told them not to allow public opinion to influence their discussions as they determine Christopher Alexander Falconer's legal fate.

Falconer, 31, has pleaded not guilty to first-degree murder in the death of the 19-year-old woman, who vanished after leaving a pool hall in downtown New Glasgow in the early hours of Oct. 9, 2011. Her naked, bound remains were found about a month later in a shallow grave in nearby Heathbell.

"You must consider the evidence and make your decision without sympathy, prejudice or fear," Judge Nick Scaravelli of the Nova Scotia Supreme Court told the jury, who deliberated for four hours before breaking for the evening. They are scheduled to resume Tuesday.

Scaravelli's instructions came following three weeks of testimony. He told the jury they have three possible verdicts: not guilty, guilty of first-degree murder or guilty of second-degree murder if they believe Falconer caused Kirwan's death but did not kidnap and forcibly confine her.

He told the jurors to give fair and impartial consideration to all the evidence presented and while he encouraged them to come to a unanimous verdict, they are allowed not to reach one.

"You are entitled to come to common-sense conclusions based on the evidence that you accept," Scaravelli said. "You must not speculate, however, about what evidence there might have been or permit yourselves to guess or make up theories without evidence to support them."

Falconer's criminal record was not presented as evidence before the jury.

He pleaded guilty in a separate case to second-degree murder as a teenager for strangling a cab driver in 1998. He was 15 at the time of the murder, but was ordered to stand trial as an adult. He was granted full parole after serving 12 years in prison.

He was serving time for weapons and drug offences at the Dorchester Penitentiary in New Brunswick when he was arrested in May 2012 in connection with Kirwan's murder.

In closing arguments last Friday in the Kirwan case, defence lawyer Mike Taylor and Crown attorney Bill Gorman both asked the jury to give a common sense analysis of the evidence.

Gorman said while the case is circumstantial, the only logical conclusion based on the evidence is that Falconer committed the offence. But Taylor said there are a number of other plausible explanations that create a reasonable doubt.

During the trial, the victim's boyfriend, Mason Campbell, testified that he was supposed to pick up Kirwan at a convenience store the night she went missing, but she never arrived.

The province's chief medical examiner told the court that Kirwan, an aspiring nurse, bled to death after being stabbed at least 10 times, including once through her heart.

Dr. Matthew Bowes said Kirwan was able to mount a vigorous defence against her attacker, despite high levels of codeine in her system, leaving her with defensive wounds on her hands.

However, Bowes said Kirwan's body was too decomposed by the time it was found to determine a time of death.

The trial also heard from a number of witnesses, including Falconer's former girlfriends and Kirwan's parents, as well as detailed testimony on fingerprints and toxicology.

Court also heard a recorded phone call between Falconer and his father in November 2011, about six months before he was charged, in which Falconer said he should plead guilty to Kirwan's death to protect his family from stress.

On Monday, Taylor expressed relief that his client's fate was now in the hands of the jury.

"I think the jury has all the information they need to make a proper verdict," he said outside court. "I'm relatively comfortable in that sense, but I'm glad it's done. It's been a long haul."

Taylor said Falconer, who sat silently during the judge's instructions to the jury, was anxious but taking a wait-and-see approach to the verdict.

Meanwhile, Kirwan's family continues to struggle with the loss of their loved one, said Crown co-counsel Patrick Young.

"They seem strong and they seem to be doing OK, but you can tell it's still very difficult for them," he said outside court.

Gorman said he believed the jury has the necessary tools to make a fair, impartial decision.

"We feel that we presented a solid case, that the jury are an intelligent group of people and they'll be able to carefully consider the evidence they have before them."