Residents of the bucolic towns of Lafayette, Moraga and Orinda have long known to guard their pets and backyards from coyotes prowling in the shadows, behind trees and around garbage bins.

"They howl behind my house every night," said Melodi Dewey, a Lafayette resident. "There's a pack of them on the other side of my fence. I have to keep my dogs from going outside at night."

But Dewey and others in the Contra Costa County area dubbed Lamorinda are warier than ever these days and just as surprised as wildlife officials after a string of coyote attacks this year left three people bitten and injured, the latest one Tuesday behind Diablo Foods in Lafayette.

And what's particularly alarming is that the same coyote is responsible for all three attacks, according to authorities. Lab results showed Thursday the DNA in the saliva around the latest victim's wounds matched the DNA found in previous attacks.

Although California Department of Fish and Wildlife officials have trapped and killed four coyotes in the area within the past couple of weeks, they have not yet caught the culprit in Tuesday's attack and those on Dec. 4 at Campolindo High School in Moraga and in July not too far from Moraga Commons Park.

"I've never seen anything like this in my (24-year) career ... one animal so aggressively attacking people," Capt. Patrick Foy of Fish and Wildlife's law enforcement division said in an interview Thursday.

Coyote attacks on humans are unheard of for Lamorinda residents, who have always considered the animals to be a nuisance but never a threat to their own safety — until now.

"They eat my chickens," said Virginia Steuber, another Lafayette resident. "We get all the vermin. There's one really big, strong coyote who comes by. But the only coyotes I see are the ones stalking my chickens. ... I was very surprised to see that actual people got bit."

The latest victim, an employee of Diablo Foods in the 3600 block of Mt. Diablo Boulevard in Lafayette, did not want to be named or interviewed for this story. But Juan Mújica, a coworker who was with him when the coyote struck, explained on Thursday what happened.

Mújica said his coworker was sitting under a tree in a parking lot near the grocery store. It was just before 7 p.m. and dark when his coworker suddenly "jumped up for no reason" and exclaimed he had just felt a sharp bite on his leg.

"He said, 'I think it was a dog,' but another lady who was (leaving work nearby) started screaming, 'Oh my god, it's a coyote!' " Mújica said. "We were scared. My coworker's friend started climbing the tree, and I pulled out my flashlight and told him to run."

Mújica didn't get a close look at the coyote but said it appeared to be no larger than a small dog. A week earlier, he and another coworker had spotted a coyote roaming near large garbage containers behind the store.

Diablo Foods co-owner Connie Collier said the victim is "doing fine" and recovering from the injuries. She suggested the store may direct employees to take their breaks on the other side of the building, away from the garbage containers.

The sneak attack was the third in the Lamorinda area this year. A man running the track at Campolindo High School was ambushed and bitten by a coyote in the dark. And a boy was bitten on July 9 about 1.5 miles south of Moraga Commons Park.

The incidents are part of an outlier year for coyote attacks on humans in California. Although there's usually one such attack in a year, Fish and Wildlife has counted eight in 2020 so far, Foy said. Locally, besides the three in Lamorinda, there was a coyote attack in Dublin Hills Regional Park earlier this year. The other four attacks happened in Orange and San Diego counties

Foy added that officials have not yet determined why the coyote suspected in all three Lamorinda attacks is behaving so aggressively or whether it might be rabid.

"That will be part of the test if we can get a hold of this singular animal," he said.

The coyote attacks put at least one person strolling downtown Lafayette on Thursday on slight alert. After one of his regular walks at the Lafayette reservoir, Walnut Creek resident Andy Wenzel said he doesn't often see coyotes out on the trails. But he has seen the news of recent attacks.

"When I was walking today, I kept an eye out for any potential wildlife," Wenzel said. "'Be aware of your surroundings' is my thing now, I guess."