A crucial video in the manslaughter trial of Const. Daniel Montsion has been released to the public, though it has not been accepted as evidence and most of it has not been shown in court.

Surveillance video shows the confrontation between Abdirahman Abdi and police in front of his apartment building at 55 Hilda St. on July 24, 2016.

Abdi officially died in hospital the next day.

The Crown intends to use the video to prove Montsion used excessive force during the altercation, and that he is responsible for Abdi's death.

The video was released following a request from CBC Ottawa and the Ottawa Citizen.

Justice Robert Kelly released two versions of the video showing Abdi running toward the doors of his apartment building, followed by Const. Dave Weir, who has not been charged.

On Monday the court saw approximately 30 seconds of both videos.

The start of the video shows Weir hitting Abdi several times with his baton and kicking him before Montsion arrives. It appears Montsion punches Abdi at least once before the two officers push Abdi to the ground.

The next part, which has not been viewed in court, appears to show Montsion punch Abdi several times shortly before Abdi stops moving.

Video contested

The majority of the video hasn't been shown in court because the defence claims the Special Investigations Unit (SIU) mishandled the files. Investigators had technical problems with the original video file.

The defence is building a case to have all the videos deemed inadmissible, which would mean the judge may never see any of them in their entirety.

Over the course of the investigation, multiple copies of the video were created. The trial has focused on a low-quality 29-minute screen capture and a copy that appears to run at a slower speed. The difference between the two is at the crux of the defence's argument.

Two versions of the surveillance video at the centre of Const. Daniel Montsion's manslaughter trial shown side-by-side. The defence argues the video on the right appears slower and smoother than the version on the left, which was secured as digital evidence. The defence says the version on the right was shown to several expert witnesses, calling their testimony into question. 0:23

The screen capture was the only version of the video secured as digital evidence before the trial. The original surveillance video and the slower version never made it to the SIU's central evidence registry and was not disclosed to the Crown and the defence until the day before the trial.

The problem facing the Crown now, is that the slower version was shown to key expert witnesses during the investigation, including the pathologist and the blood-spatter expert.

If the defence's argument carries that could threaten major elements of the Crown's case.

The court will hear more testimony about the contested videos on Wednesday.