The officers were called after the cougar had an encounter with a German Sheppard and the dog's owner as they walked on a trail along the Capilano River near Park Royal mall.
"It was just laying there on the ground, [so] I was able to approach him and killed him on site there," said conservation officer Simon Gravel. "It definitely is a public safety concern for us to have a cougar walking in so high-density, residential area in the middle of the day like this."
Conservation officers say they have received several calls of a cougar jumping into backyards and on to balconies and decks over the past two weeks.
Craig Pamplin saw a cougar while cycling through Klahanie Park on Wednesday.
"I saw a large cat come out of the greenway," he said. "It was not aggressive at all, it was kind of timid ... I'm sure it wasn't happy to be out at midday like that. I wasn't worried at all."
Earlier this week, a trio of cougars and bears was caught on surveillance video at a salmon hatchery in Port Moody.