RICHMOND, B.C. -- Warning: This story contains offensive language.

A Richmond man is speaking out after a violent encounter with a neighbour who’s a Canada Border Services Agency officer.

Nathan Lau says he’s had a few unpleasant run-ins with the officer before he was sucker punched in the face last Thursday.

Lau says he and a friend were on their way to the parking garage of his townhome complex when they ran into the officer.

"He just made eye contact with me for two, three seconds and then made a kissing gesture and then called me the derogatory f-word,” Lau says, referring to a homophobic slur.

He says after that, the neighbour returned to the garage and it appeared like he was recording them on his phone.

That’s when Lau used his friend’s phone to record their interaction.

"Trying to record me?" Lau can be heard saying in the video.

"Don’t fucking walk up on me," the neighbour says in response.

The video is cut short after the neighbour walks up to Lau and the phone drops.

"When I stuck my hand out to keep some distance, I guess that's when he sucker punched me because my glasses fell out and the phone fell on my hand — and then I don't really remember what happened after," Lau tells CTV News.

Another video shows Lau being held in a headlock by the off-duty border agent.

"He told my friend that he’s an officer, so I’m asking him, 'Why are you putting me in a headlock then if you’re an officer?' He didn’t answer my question," Lau says.

Lau has suffered an infraorbital fracture and concussion, he says.

"I actually haven't been sleeping at home because I'm fearful," he says.

Previous run-ins with the border-agent

Lau says he’s lived in the complex for nearly a decade and hasn’t had any issues until he met that neighbour in May.

He says he was walking his two dogs in their courtyard when a cat on a leash lunged towards them.

He says the neighbour came out of the home and confronted him.

"Some guy comes out, rushing out of his unit and says, 'Hey do you have a problem with me and my cat?' I turn around and I’m kind of confused and I’m like, 'No, but why is your cat alone outside where it can interact with other people?'"

He says the encounter lasted up to 10 minutes and at one point, the officer called him a nerd and skinny.

The second time, Lau was with his girlfriend who noticed the man staring at her "uncomfortably" from inside the home.

"He suddenly, like, rushed out and just came really close to Nathan, shoved him. Completely broke social distancing measures and like, pressed his face against Nathan, and just basically was telling him, 'Yo, square up, like, let's fight or something.' I was flabbergasted," says Isabel Chuong.

"He was still just like shouting insults at us. And that's when he basically said, 'Go back to your own country, like don't tell me how to raise my cat.' I was just disgusted by that stereotypical, like, racist tone," she says.

'Fist-fight between neighbours': RCMP

Richmond RCMP say when officers responded, one of the men said they’re a CBSA officer and he was the one who called 911.

"Initially, both parties admitted to losing his cool and neither party wanted further action by police. It was deemed a consensual fight," says Cpl. Ian Henderson in an email statement.

He says it first appeared to be "a fist-fight between neighbours" but the case has been reopened after Lau indicated Thursday that he wanted this to be investigated further.

Mounties also say Lau is known to them with a history of assaults and causing a disturbance.

In response, Lau says it happened a few years ago and is unrelated to the border agent allegedly assaulting him.

CBSA investigating

Lau says it was alarming to learn that his neighbour works for the CBSA.

“To be like a border agent, an immigration officer, and to racially profile someone and to attack them — probably because of that — is very stunning,” he says.

The CBSA says it is reviewing the incident.

"A thorough investigating of the employee’s conduct is ongoing. Any employee who breaches CBSA’s strict code of ethics and behaviour will face disciplinary action. This matter involves a single CBSA officer and is not representative of the integrity and professionalism of thousands of CBSA employees who carry out their duties in an exemplary manner," it says in a statement.

CTV News knocked on the officer’s door and no one answered.