The first-degree murder trial of a Moncton-area man accused of killing his ex-girlfriend began Wednesday with the Crown prosecutor saying the blood of the victim was found on the jeans of the accused.

Fred Prosser, of Shenstone, is charged with first-degree murder, sexual assault causing bodily harm and sexual assault in the death of Sabrina Patterson, the 25-year-old mother of his two children.

Patterson, of Riverview, went missing on Oct. 29, 2010. Her body was found in a wooded area near Shenstone on Nov. 6, 2010.

On Tuesday, Prosser formally pleaded not guilty to the charges and told the judge he was ready to be tried in front of the five men and seven women selected for the jury.

Wednesday, Crown Prosecutor Annie St. Jacques opened the trial by saying she intends to prove that Prosser sexually assaulted Patterson and strangled her to death. St. Jacques said she’ll present evidence showing that Prosser’s blood was found on Patterson’s body, and his DNA was found on her neck.

St. Jacques said she’ll also introduce evidence that Prosser threatened to kill his ex-girlfriend before her death.

RCMP take the stand

Fred Prosser is charged with first-degree murder in the death of his ex-girlfriend, Sabrina Patterson. (CBC)

The first witness in the trial was RCMP Sgt. Blake Keirstead, who started working on the case Nov. 1, 2010, after Patterson was reported missing.

Keirstead said the RCMP initially thought both Patterson and Prosser were missing after her car was found in a Riverview strip mall parking lot. The police launched a search, including ground search and rescue teams and an aircraft.

On Nov. 4, 2010, the RCMP found Prosser at his parents' home, where he had been living, and he was arrested.

Keirstead said Patterson’s remains were found two days later, approximately five kilometres from Prosser’s home.

He said more than 120 RCMP officers have been working on the file, and more than 500 exhibits were retrieved after they executed search warrants.

In the cross examination, defence lawyer Scott Fowler questioned why, in June 2012, several exhibits seized went missing, but then suddenly reappeared this month.

Fowler also pointed out that Prosser had no scratches or injuries on his body when he was arrested by the RCMP.

Second trial scheduled for case

Prosser was originally scheduled to stand trial in Patterson's death in July, but the proceedings were halted on the first day when one of the selected jurors was found to have made comments about the accused on Facebook.

The judge at that time declared a mistrial, saying he had no choice because there was a risk the juror may have tainted the rest of the jury.

Dale Patterson, Sabrina Patterson's brother, said he doesn't expect that to happen again.

"With the judge knowing, he doesn't want any mistrial, he doesn't want anything to happen either," Patterson told CBC News on Tuesday.

"He's kind of on the same side as us as far as wanting things done right and that's all we want. We just want it done right."

Patterson said his family was trying to stay strong through the process.

"They're dealing with it better than they were just because it's been two years, but it just seems that it's always being brought up and especially coming from a small town it's hard to have any peace of mind," he said.

"It's been all over the news and stuff like that so it has been a hard month."

Five weeks have been set aside for the trial. The Crown expects to call about 40 witnesses.