Two renditions of a surveillance video clip at the centre of Const. Daniel Montsion's manslaughter trial show slightly different versions of the events leading up to the death of Abdirahman Abdi, court heard Monday.

The video is a key piece of evidence for the Crown, which intends to use it to prove the Ottawa police officer used excessive force and was responsible for Abdi's death in July 2016.

Montsion has pleaded not guilty to manslaughter, aggravated assault and assault with a weapon.

The surveillance video, shot from the lobby of Abdi's apartment building at 55 Hilda St., shows Abdi running toward the front doors before a police officer catches up to him.

That officer, Const. Dave Weir, appears to hit Abdi with his baton, then kick him. Seconds later, Montsion arrives and the two officers push Abdi to the ground.

2 versions, 2 speeds

Both versions of the clip, played in court for the first time Monday, last less than 30 seconds.

One version is a low-quality screen capture of the original CCTV file first obtained by Ontario's Special Investigations Unit (SIU), which was called in to probe the incident after Abdi died.

The officers' movements in that version, which is shot at 10 frames per second, appear jerky and faster than in the second version, an MP4 export of the original digital file. In that version, the officers' movements appear slower and smoother.

It was that version of the video that the Crown shared with the defence the day before the trial began, a last-minute surprise defence lawyer Michael Edelson has referred to as "a Sunday bombshell."

Different versions shown to experts

On Monday, defence lawyer Soloman Friedman pointed out that Abdi appears to fall to the ground more slowly in the second version of the video.

But SIU forensic investigator David Robinson would only concede that the second video is "smoother" than the first, perhaps because of its superior quality.

It's an important distinction, because different versions of the video were shown to various expert witnesses consulted in the case, the defence claims.

The defence claims the pathologist who recommended Abdi's death be deemed manslaughter did so because he'd been shown the slowed-down version.

Court also heard Monday the blood-spatter expert consulted in the case had viewed the slower version, despite an earlier decision not to reveal any video evidence to that witness.

The claims come on the third day of Robinson's cross-examination, as the defence dissected every detail of how evidence in the case was gathered and stored.

Montsion's lawyers made the case that video evidence was mishandled after investigators encountered technical problems playing and exporting the file.

Cross-examination continues Monday afternoon.