The Fairfax County Police Department has released footage from an officer’s body camera showing a knife-wielding woman slashing the officer several times before he shot and killed her in the hallway of her Reston apartment building last month.

The footage, released Monday, shows Sydney Wilson’s attack on Officer Peter Liu that left him with several knife wounds, including a large gash on his forehead.

The incident occurred Sept. 16 in the 11800 block of Sunrise Valley Drive in Reston. Officer Liu was outside Wilson’s apartment to conduct a welfare check on the woman, who police said had a history of interactions with authorities.

In the bodycam footage, Wilson opens her door, sees the officer and immediately slams it in his face. Officer Liu knocks again and waits outside the door.

Wilson soon reopens the door, says “How are you?” and swipes at Officer Liu with a kitchen knife.

The officer jumps back and says “Jesus Christ!” before unholstering his gun and retreating down a short hallway.

Wilson — who stood 6-foot-5-inches and weighed 330 pounds — walks menacingly toward Officer Liu as the officer orders her to “back up.”

The footage shows Wilson barreling toward the officer and trying to slice him with the knife. Officer Liu ducks to his right and slips past Wilson, who starts chasing after him.

Officer Liu fires three shots at Wilson, who collapses in the hallway. She was pronounced dead at a hospital later that day.

“Our police officer acted valiantly. He certainly exhibited grace under pressure,” police Chief Kevin Davis said last month hours after the shooting. “He tactically repositions himself in an effort to defuse the situation, but he was faced in a scenario that the only way out — and again, I’ve seen the body-worn camera footage — was for him to protect himself from being cut even more than he already was.”

Officer Liu is a 14-year veteran of the department who is trained in crisis intervention, police said.

He remains on administrative duty as the investigation of the fatal shooting continues.

• Matt Delaney can be reached at mdelaney@washingtontimes.com.