Fred Prosser is charged with first-degree murder in the 2010 death of Sabrina Patterson. (CBC)

RCMP found a pair of jeans with brownish stains on them in Fred Prosser's bedroom, the jury at his first-degree murder trial heard on Friday.

Cpl. Pat Gould, a forensics expert, said he did a presumptive test for blood, which was positive.

Prosser, 33, of Shenstone, is charged with first-degree murder, sexual assault causing bodily harm and sexual assault in the 2010 death of his ex-girlfriend, Sabrina Patterson.

The Crown alleges Prosser sexually assaulted Patterson, the mother of his child, and strangled her to death.

Patterson, 25, a mother of two from Riverview, went missing on Oct. 29, 2010. Her body was found in a wooded area near Shenstone on Nov. 6, 2010.

Gould told the court the size 42 Denver Hayes jeans, which were on the floor in front of Prosser's dresser on Nov. 7, would have been sent for further testing.

Earlier this week, during opening statements, Crown prosecutor Annie St. Jacques said the blood of the victim was found on the jeans of the accused.

St. Jacques said she will also present evidence showing Prosser's blood was found on Patterson's body and his DNA was found on her neck.

RCMP Cpl. Stephen Campbell, another forensics expert, also testified on Friday. He said he was sent to Prosser's home armed with a search warrant in June 2011, seven months after Patterson's body had been found.

He found a cooler outside the garage, which contained a jacket with the name Sabrina on the arm, an open purse and a pair of sneakers. Some of the items were wet, he said.

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