Accused triple murderer Basil Borutski's fate could be in the hands of the six women and six men of the jury early next week, the judge told the jurors after the Crown closed its case and Borutski, who is representing himself, declined to testify or call witnesses Wednesday.

Closing arguments in the high-profile trial are now expected to be heard Tuesday after the Crown called its final witness in the case — a firearms expert — on Wednesday.

Because a defence was not presented, the Crown will give the first closing statement. Borutski will then have the opportunity to give one, if he so chooses.

So far he has not spoken a word in court.

In total, the Crown called about 45 witnesses in just 17 days of proceedings. The trial had originally been scheduled to run into January, but unfolded "twice as fast as anybody could expect," Ontario Superior Court Justice Robert Maranger told the jury.

Prepare to be charged, judge tells jury

The jurors were instructed by Maranger to be prepared for the possibility of being charged and beginning deliberations. When that happens will depend on how long closing arguments take on Tuesday. Either way, Maranger told the jurors he anticipates Borutski's fate will be in their hands next week.

The bodies of Carol Culleton, 66, Anastasia Kuzyk, 36, and Nathalie Warmerdam, 48, were found at three separate crime scenes in and around the community of Wilno, Ont., on Sept. 22, 2015.

Borutski, 60, faces three counts of first-degree murder at his trial in Ottawa.

The court entered a plea of not guilty on his behalf after Borutski refused to enter one himself.

Anastasia Kuzyk Nathalie Warmerdam Carol Culleton Basil Borutski homicide victims

The bodies of Anastasia Kuzyk, Nathalie Warmerdam and Carol Culleton were found at three separate locations in and around Wilno, Ont. Kuzyk and Warmerdam were shot with a 12-gauge shotgun, and Culleton was strangled with a coaxial cable. (CBC News)

Similar markings on spent shot casings 

Earlier Wednesday, court heard that a decades-old rusty sawed-off shotgun without a serial number, which was seized by police after Borutski's arrest, fired the shots that killed Kuzyk and Warmerdam.

Judy Chin, a forensic scientist at the Centre of Forensic Sciences in Toronto who specializes in firearms and toolmark examination, testified she examined the seized J.C. Higgins Model 20 12-gauge pump-action shotgun that court earlier heard was seized from the field in Kinburn, Ont., where Borutski was arrested, as well as spent shot shells, pellets and wads recovered in the Kuzyk and Warmerdam homicide investigations.

The shotgun has no serial number, but Chin testified she wasn't surprised to see that. The shotgun was made in the '50s and early '60s, and at that time there was no law in Canada requiring firearms to have serial numbers, she told court.

J.C. Higgins model 20 12 gauge pump action shotgun Basil Borutski trial 2017

This J.C. Higgins model 20 12-gauge pump-action shotgun was recovered from the field in Kinburn, Ont., where accused triple murderer Basil Borutski was arrested by police. A firearms expert testified the shotgun was used to fire the shot shell cases recovered from the Kuzyk and Warmerdam homicide scenes. (Kristy Nease/CBC)

The shotgun was rusty, cut down and in overall "poor condition," but it worked. The rust could have been caused by exposure to water and air as a result of being left out in the open or being stored improperly, she testified.

Chin told court she used the shotgun to fire five test shots and compared those spent casings with those recovered from the crime scenes, and found they bore markings unique to each other.

"There is an agreement of class and individual characteristics between the comparison items," her report concluded.

During Borutski's confession to police, which was heard in court weeks ago, he told police he found the shotgun and ammunition for it. Court also heard a firearms licence was among the items found in his wallet.