VANCOUVER -- A British Columbia police officer facing both a civil lawsuit and a murder charge says he fired his rifle after a "distraught and violent man" pointed a handgun at police during a tense standoff.

In a response to the lawsuit filed by the dead man's daughter, Const. Jordan MacWilliams said he had a "reasonable fear" the man would cause death or grievous bodily harm to himself or others

Mehrdad Bayrami, 48, was fatally shot outside the Starlight Casino in New Westminster in November 2012, after police allegedly rescued a female hostage and a five-hour standoff ensued.

B.C.'s police watchdog, the Independent Investigations Office, led a probe into the shooting. Last fall, the Crown approved a second-degree murder charge against MacWilliams -- a rarity for a B.C. officer.

Nousha Bayrami claims in her lawsuit against the constable and his employer, the Corporation of Delta, that her father was walking backwards away from police when MacWilliams suddenly shot him without warning or justification.

She accuses the officer of "gross negligence or malicious or wilful misconduct." Bayrami claims she has suffered financial losses as a result of her father's "wrongful death," and has been deprived of his "love, care, guidance and support."

None of the allegations have been proven in court. The officer's criminal trial is due to begin in October.

The officer's response to the civil claim says police were called to the casino on Nov. 8, 2012, after an employee saw live security footage of the staff parking lot, where a man was threatening a woman with a handgun.

The man, later identified as Bayrami, fired the gun into the woman's vehicle and dragged her about 300 metres to an area near an intersection, the response alleges.

"The confinement of the female victim ended when she was rescued by Constable MacWilliams," and by two other officers, the document states.

The daughter's lawsuit describes the initial confrontation as a "domestic dispute."

The incident then turned into a standoff where Bayrami stood still while holding the gun and occasionally pointing it in the air or at his own head, the response says.

MacWilliams was assigned the role of "lethal overwatch," which meant he was responsible for providing cover to other officers and using deadly force if necessary. The officers set up a 20-metre containment area.

After a long period, Bayrami began walking towards MacWilliams while holding the handgun "on or near the trigger," the document alleges. Police then deployed "less lethal measures," including a noise and flash device and rubber bullets.

When Bayrami moved the handgun from pointing in the air to aiming it at the officers, MacWillams fired his rifle "in response to the threat," the document states.

The man was rushed to hospital, where he died several days later.

Jeremy Poole, the lawyer representing both MacWilliams and Delta, said it's likely the criminal matter will be resolved before the lawsuit makes it to court. He said he expects there will be some evidence overlap between the two.

Nousha Bayrami's lawyer Cameron Ward did not immediately respond to requests for comment.