Paul Saliba believes he would have been charged for assaulting a corrections officer after an incident in a prison parking lot in 2017 if it weren't for security footage of the incident that shows he never touched the prison guard.

In fact, an internal investigation by the Correctional Service of Canada found that the security video shows the prison guard charging at Saliba, who has a disability, grabbing him by the coat and pushing him against a vehicle.

Saliba wants the guard to face consequences. After pushing for an internal prison investigation over the incident, and laying a private charge that was dismissed, Saliba has launched a $500,000 civil suit against the guard and the Attorney General of Canada.

"There's a law for us and there's a law for them," said the Marmora, Ont., man. "Luckily, there was the camera."

The 69-year-old has been fighting to change what he believes is a double standard in the justice system ever since he was allegedly assaulted outside the medium-security prison in Bath, Ont., about 245 kilometres east of Toronto, in February 2017.

Gough's lawyer and the Correctional Service of Canada declined to comment on the case directly because the matter is before the courts.

Watch: A security camera caught the interaction between Paul Saliba and a guard

An internal Corrections Canada investigation found that this security video shows a prison guard charge at Paul Saliba, grab him by the coat, and push him against a vehicle. 0:43

Saliba was on his way to visit his son there, but never made it inside the prison before he says corrections officer Darin Gough told him his visit was cancelled and followed him back to his car.

Dispute over disabled spot

Their initial encounter was a disagreement over Saliba using a disabled spot in the staff prison parking lot — he'd gotten permission from the Correctional Service of Canada to park there about four months earlier. Saliba has an accessible parking permit due to back, hip and shoulder injuries from a serious car accident and the staff lot is closer than the visitor lot.

"I didn't do anything to him other than try to explain to him that I was parked in a legal parking spot," said Saliba.

In the parking lot, Saliba refused to give Gough his name for fear of retribution against his son. Gough was taking photos of Saliba's licence plate to identify the visitor when Saliba reached into his car to get his cellphone.

"I was going to try and take pictures of him but I'm not savvy with that," Saliba told CBC News. "The next thing I know he grabbed me by the lapels of my jacket and slammed me up against the vehicle next to my vehicle."

Crown stays charge against guard

Saliba reported the alleged assault to Ontario Provincial Police in Odessa, Ont., and the prison's warden. Police never laid charges, but following an internal prison investigation, Saliba had a private charge laid against Gough. Any private citizen can lay a charge after presenting their complaint to either a provincial court judge or a designated justice of the peace.

Last month, the Crown intervened in the case and stayed the charge.

"They said it wasn't worth the effort to get a conviction for what his penalty would be," Saliba said. "[The Crown] figured he'd get 10 hours of community service and maybe have to write an apology letter."

With that fight over, Saliba is now concentrating on his civil lawsuit against Gough and the Attorney General of Canada, saying it's "the only way to get their attention."

In the lawsuit, Saliba alleges Gough "concocted false criminal accusations" against him "to cover up Officer Gough's own wrongdoing" and that the Correctional Service of Canada owed him a duty of care as a visitor at their institution.

Corrections officer Darin Gough, left, spoke to Paul Saliba outside the entrance of Bath Institution before walking the visitor back to his car. (Bath Institution surveillance video)

Both Gough and the Correctional Service of Canada have filed statements of defence in the case. In the court filings, Gough denies any and all alleged wrongdoing and claims anything he did while interacting with Saliba was "in accordance with his assigned duties."

The Attorney General of Canada denies all allegations of liability made by Saliba, but says the corrections officer was not acting in accordance with his assigned duties during his interaction with Saliba.

Despite video, guard adamant he didn't touch Saliba

Following the 2017 incident, Gough made a complaint to OPP's penitentiary squad, claiming that Saliba had assaulted him. Later, in an internal investigation, he said that Saliba had been aggressive in their interaction and grabbed him, according to the internal investigation report.

After the incident the prison guard told his superior that he didn't know what Saliba was retrieving from his car and so he "adopted a defensive stance by raising one arm to block him." That's when Gough says Saliba grabbed his wrist.

In conversations with his superiors, two interviews for the internal investigation, and his statement of defence in Saliba's civil lawsuit, Gough has remained adamant that he never touched Saliba — even when shown the video.

A month after the incident, in an interview with internal investigators, Gough indicated that at the time he thought he'd been assaulted, "but after analyzing events" realized Saliba "was only trying to regain his balance" by grabbing his arm.

Bath Institution is a medium security prison in Bath, Ont., about two and and a half hours east of Toronto. (CBC)

In that same interview with investigators, Gough said he didn't need to see the security footage because "he knew what had happened." In a second interview two months later, Gough said it's the camera angle of the security footage that makes it look like he touched Saliba and Gough was "the true victim" of the incident.

Investigators disagreed.

"After numerous reviews of the CCTV video, the board is of the opinion that [Gough] charged at Mr. Saliba and grabbed him by his coat in the upper chest area and pushed him into the vehicle," says the report. "There is no doubt [Gough] did touch Mr. Saliba, although he is adamant he did not."

It's unclear what, if any, discipline Gough faced in connection with the incident. In a statement the Correctional Service of Canada said, "for privacy reasons, information about employee misconduct is not publicly available."

But the service also said that "employees are expected to act according to the highest legal and ethical standards, and are subject to the rules of professional conduct and code of discipline."

Previous visitor incident with guard

Saliba says he almost dropped his case against Gough over a year ago, but changed his mind when he came across media reports about another incident Gough was involved in with a visitor at Bath Institution a year before his interaction with Saliba.

The February 2016 incident involved a visitor's cellphone which registered an "intruder selfie."

On her way to visit her partner in prison, Tammy Truesdell's vehicle was searched by a drug dog and the dog's handler. Truesdell left her phone in the car, and when she went to check her phone after her visit she found an email from a security feature app.

The email was titled "someone tried to unlock your hangouts" and included a close-up photo of Gough, the drug detector dog handler who had searched the car, according to federal court filings.

To activate this "intruder selfie" security feature on Truesdell's cellphone, someone would have to hit the home button, press the Google hangouts app and then type in the four-digit password code incorrectly twice.

Somebody needs to be accountable. - Paul Saliba

Truesdell told her partner about the selfie and then he filed an inmate grievance. It was denied by the warden of Bath Institution, who informed him that "her staff members do not break the rules and that in her view the photo was taken inadvertently," according to a federal court decision.

A security function on Tammy Truesdell’s cellphone took this photo of corrections officer Darin Gough while he was searching her vehicle before she visited Bath Institution in February 2016. (Federal court record)

Gough was adamant he did not attempt to access the phone, but must have touched the screen in a way that triggered the notification when he was moving the phone into the car's glove box.

The inmate grievance was denied at each stage of the process until a judge dismissed the couple's application for judicial review because the potential wrongdoing happened to Truesdell, a visitor, not to an inmate.

However, in her decision to dismiss the case, Justice Glennys McVeigh noted that "the idea that two incorrect four-digit codes could be inputted simply by moving a phone into the glovebox is an unlikely explanation for what occurred."

"I almost gave up," Saliba told CBC Toronto. "When I read [about that incident] I decided I can't let this go … somebody needs to be accountable."