There are at least seven distinct versions of the video evidence the Crown has said is key to convicting Const. Daniel Montsion for manslaughter, aggravated assault and assault with a weapon in the death of Abdirahman Abdi.

They each capture Abdi's violent arrest outside the doors of his Hilda Street apartment building on the morning of July 24, 2016.

But no two versions are quite alike. Subtle differences in speed, running time, resolution and frame rate have made it difficult to know which one tells the true story of the events that preceded Abdi's death.

On Monday, Montsion's lawyer's will argue that thanks to the negligence of the Special Investigations Unit (SIU), it's not just difficult, but impossible — and also impossible for Montsion to have a fair chance to refute the charges.

They have asked the judge to stay all charges, or at least deem all versions of the video inadmissible.

It's up to the Crown to prove that not only was the SIU not negligent, but also that at least one of these videos is accurate enough to show in court.

The original surveillance video

The trouble with the video started only hours after Abdi was taken away by ambulance.

SIU forensic investigator David Robinson was handed a thumb drive by a fellow investigator shortly after he arrived on the scene.

The video came with proprietary software and wouldn't play smoothly on his computer. Sometimes it would freeze. Other times, it would appear to randomly speed up.

Robinson chalked it up to his own inexperience using the program.

But according to an independent expert retained by the Crown, the video was likely corrupted when it was extracted from the recording system.

That expert's report hasn't been shown in court.

That wasn't the only problem. Robinson also had trouble copying the files to a DVD to be secured as digital evidence at the SIU's central registry.

He forgot about it, and it wasn't logged as evidence until more than two years later, after Montsion's trial had already begun.

A longer version of the video secured as digital evidence in the trial of Const. Daniel Montsion. It appears to show Abdirahman Abdi being kicked and punched by police officers in front of the apartment building at 55 Hilda St. 5:51

The screen capture

Robinson did manage to make a screen capture, using a program that basically recorded what played on his screen.

But there are two problems: the copied video contains all the same issues as the original, while only being recorded at 10 frames per second — a third of the original quality.

As an example, when Abdi is pushed to the ground, he appears standing in one frame of that video and on the ground the next.

It's the least accurate of all the videos, but it's the only one that was initially secured and disclosed.

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 Kavcic video

Robinson reached out to his manager for help through this ordeal.

Forensic identification manager Frank Kavcic showed him step-by-step how to export an MP4, and created a two-minute, 14-second video that captured the altercation between police and Abdi.

However, Robinson forgot all about Kavcic's version when he went back to his desk.

Kavcic later shared it with the blood spatter expert and the pathologist who determined Abdi's death to be manslaughter, according to testimony heard in court.

But it wasn't shared with Montsion's lawyers until the night before the trial. It also doesn't have any timecode that would allow experts to verify that it runs in real time.

Two other copies were made from the surveillance system at 55 Hilda St. They were put onto red and green thumb drives and eventually made their way into the Crown's hands.

According to the expert report, it's unclear how these copies came to be. They also seem to have similar playback issues as the original.

The final hope

The Crown has put its hopes in the very last video. Their video expert, Ed Segeren, deconstructed the surveillance footage by creating an image out of each individual frame.

He then used video editing software to stitch the images together into a new video file.

This one contains the timecode and other data from the original video, but actually plays smoothly, according to Segerin. The Crown intends to argue that of all the videos, it presents the most accurate version of what happened that morning.

The Crown's video expert deconstructed the surveillance footage by creating an image out of each individual frame, then used video editing software to stitch the images together into this new video file. 0:26

Segeren also created another video using the same method, but zoomed in on the action

But there's a trade-off — the resolution suffered. The new video is about a quarter of the size of a standard definition video frame. In other words, fine details were lost in the reconstruction.

Even if the Crown wins the battle to keep all seven videos on the table as potential evidence, they'll still have a long road ahead if they want to prove the reconstructed video should be admitted.