10/14/2014 02:30 EDT | Updated 12/14/2014 05:59 EST

Luka Magnotta trial: Bloodstains described by forensic expert

A forensic biologist guided the jury in the LukaMagnotta first-degree murder trial methodically through photographic evidence found at the crime scene, explaining each bloodstain identified by police.

Jacinthe Prévost, a forensic biologist with 18 years' experience, was called to the apartment in Montreal's Snowdon neighbourhood in the early hours of May 30, 2012. She spent more than two hours analyzing bloodstains and spatter at the scene, and later treated 94 pieces of evidence as she compiled her report.

Prévost told the court she examined stains found in the rooms and through DNA testing identified the blood as belonging to the victim, 33-year old Jun Lin. She also found the DNA of a man later identified as the accused, LukaMagnotta.

Magnotta has pleaded not-guilty to first-degree murder and four other charges, but has admitted to the physical act of killing Lin, along with the facts outlined in the other charges. His lawyer intends to prove Magnotta is not criminally responsible because of mental illness.

The Crown alleges the killing was premeditated.

The forensic biologist described in detail the numerous little blood spots found near the window and radiator close to the bed. She explained to the jury that small drops indicate a forceful blow was used, and because of the size and angle of the drops, the witness presumed the blow occurred near the foot of the bed.

Prévost noted the bedsheets had folds that indicated they were newly bought, and there was a burgundy shower curtain on the bed underneath a brown flat sheet.

There was an “enormous amount” of decayed blood on the bed, the witness testified, and blood seeped straight through the mattress, which Prévost said looked as if it had been flipped in a possible attempt to hide the large stain.

The witness also detailed the large bloodstains found in the freezer and the refrigerator, saying it looked as though something was placed on the grille rack that was dripping with blood, forming a pool at the bottom.

Prévost said blood in the bathroom sink and bathtub was diluted, and the sink was likely wiped clean. The witness explained she noted all the stains found, but did not analyze all of them, since she believed she had enough to determine whom the blood belonged to.

Expert watched video for clues

Prévost told the court that when she arrived on the scene, investigators informed her there was an online video that appeared to show parts of the killing.

She testified she chose to watch it once to help her identify where to look for bloodstains, and watched it again later while examining the exhibits she took from the scene.

Prévost also described some of what she saw in the video, including a man whose face is hidden by a hooded sweatshirt stabbing a body laid out on the bed.

The video, which has been referred to by several witnesses, has not been played for the court. However, it is expected to be entered into evidence later this week. 

Officer recalls strong smell from crime scene

Earlier in the day, the trial briefly heard from the first patrol officer to enter the apartment on May 29, 2012.

Peter D’Avola, who was given the task of going in to find either possible victims or a suspect, testified he was struck by a strong chemical smell, stronger than bleach, mixed with the smell of a body, when he quickly walked through the apartment.

He stayed a total of 15 minutes, he told the court, and found all the windows and doors shut but balcony door unlocked.

The officer, dressed in uniform, testified that he glanced around the studio apartment and noticed a lime juice bottle on a table and what looked like bloodstains. D'Avola said he was most struck by the sheets found on the bed.

He said they looked too big, as if they were king-sized, for what seemed to be a double bed.

The trial continues this afternoon with more testimony from Prévost.