Retired Washington Department of Fish and Wildlife investigator Gary Koehler says normally cougars try to stay away from humans - and that's why Saturday's fatal cougar attack near North Bend is such a surprise.

"This is an extremely rare event," said Koehler, who was a research scientist in charge of carnivore investigations. "There was only one other fatality that's known here in the state. "

"Cougars, in particular, are for the most part really wary of humans," said Koehler.

Koehler says nobody really knows what may have triggered the cougar to attack two cyclists who were on a trail.

"It will probably remain a mystery," said Koehler.

If hikers do encounter a cougar on a trail, Koehler gives some advice.

"Don't run," he said, "because that can trigger a response."

Saturday's attack was the second time in the past 100 years where a cougar has killed a human in Washington state and just the fifteenth instance where a cougar has injured a human.

Koehler says the event shouldn't prevent people from enjoying the outdoors.

"I certainly have sympathy for the people involved in this incident and their families, but I don't think this is an event that should cause fear people who like to recreate in the outdoors or live in the outdoors."