KIRKLAND, Wash. — The final weeks of February brought an unusual flurry of 911 calls from the Life Care Center of Kirkland. A lieutenant at the local fire department suggested alerting county health officials: The nursing home might have been hit with another run of the flu.

Emergency crews dispatched as they would with any routine call, without hesitation, said Fire Chief Joseph Sanford.

“No one had any idea,” he said, “that covid was here.”

Covid-19, the new global threat caused by the novel coronavirus, already was barreling through the nursing home with frightening speed, turning the 100-plus-bed facility into the outbreak’s deadliest place in the United States. Within days, dozens of people in this quiet Seattle suburb would be under quarantine, including college students, three police officers and 28 firefighters.

Nationwide, at least 19 people have died after becoming infected with the respiratory virus. Fourteen have been linked to the Life Care Center, succumbing in the past two weeks, according to King County public health officials. Many more Life Care residents have been exposed to the virus, as well as some staff members. Late Thursday, officials evacuated 15 residents to local hospitals without saying why.

The more than 60 residents who remain are confined to their rooms, leaving the overstuffed furniture and polished tile halls strangely empty. Six are exhibiting coronavirus symptoms, the facility said Sunday. Seventy of Life Care’s 180 employees also are showing signs of the disease. The healthy staffers who are still working there wear blue smocks, face masks and gloves as they tend to residents around the clock. Visitors are banned, so relatives stand outside, communicating with their loved ones through window panes.

The outbreak at the nursing home has placed Kirkland at the center of the unfolding mystery surrounding the coronavirus. Washington state has been particularly hard hit, with two more facilities for seniors reporting infected residents on Friday.

The Life Care center has seen a dramatic spike in deaths since the first patient found to have covid-19 was taken from the facility on Feb. 19. There have been 26 deaths in the fewer than three weeks since then — typically, there are three to seven deaths in a month.

Thirteen of those who died tested positive for covid-19, but the center does not know how many of the others were tested for the virus.

Early Saturday, Life Care said it had received 45 covid-19 test kits, far fewer than the number of residents and staff now housed there. By that afternoon, a spokeswoman said they had received enough to test all residents.

While the facility is accustomed to dealing with infectious disease, staff were struck by the fast-moving virus, said Timothy Killian, a press liaison for the Life Care Center of Kirkland.

“Our experience with this so far has shown that the virus is volatile unpredictable,” he said. “We’ve had patients who within an hour’s time show no symptoms to going to acute symptoms and being transferred to the hospital. And we’ve had patients die relatively quickly under those circumstances. Everything we’ve learned so far is that we know very little about how fast this may act.”

For most people, symptoms are mild and might include a slight fever or a cough. The first known case in the United States was diagnosed in January in nearby Snohomish County. The 35-year-old man recovered.

But in people over age 60 — or those with diabetes, lung or heart disease or some other conditions — the virus can prove fatal. At Life Care, where elderly and sick people come to heal from broken hips and strokes, or simply to live out their frailest years, the death toll has continued to climb.

Nobody has publicly revealed how the virus got inside.

Before coronavirus, Kirkland’s biggest problems were soaring home prices and fast-paced demographic changes that left some longtime residents wondering whether having a trailer on the front lawn might upset the owners of the new million-dollar houses next door. It is a pretty, friendly city with striking views of Lake Washington and spontaneous block parties. The mayor owns a wine bar, the Grape Choice, where locals like to gather.

The flat-roofed building known as the Life Care Center of Kirkland existed for decades as a neighborhood of condominiums and family homes sprouted around it. Some new residents barely knew it was there, quietly tending to the old and the sick behind a stand of pines and small patches of emerald green lawn.

Now the nursing home is surrounded by news trucks and police cars. The quaint sign marking its entrance is a recurring image on national news. And the voices of concerned family members are being broadcast across the nation, questioning whether their relatives have been deemed “disposable.”

“If it’s not safe for healthy people to go in there, then how come it’s safe for healthy people to stay in there?” said Kevin Connolly, whose 81-year-old father-in-law is in the facility. Connolly said experts from the Centers for Disease Control and Prevention and Life Care should ask themselves whether they would want their loved ones there under the circumstances.

“If it’s safe for my father-in-law to be in there, go in there. Mike Pence, go sleep in the room next to my father-in-law for the next week, if it’s safe,” Connolly said, after the vice president announced plans to visit the region, but not Life Care Center, last week. “And if it’s not safe, then do something about it. No tweets and press conferences. Where are the boots on the ground?”

The City of Kirkland announced Friday that a federal “strike team” of doctors, nurses and other medical personnel would be sent to the facility this weekend to assist Life Care staffers who have self-quarantined there.

On its website, Life Care says the facility has more than 100 beds and they are hiring health-care workers, including certified nursing assistants, for approximately $17.50 an hour. Registered nurses willing to work the night shift are eligible for signing bonuses of as much as $5,000. The website shows people cooking, lifting weights and stitching material on a sewing machine.

Ordinarily, the Kirkland Fire Department visits Life Care roughly three times a week to tend to the sick and dying. But during the last two weeks in February, a fire lieutenant noticed that Life Care had called an ambulance 10 or 12 times for people with flu-like symptoms.

On Feb. 27, the fire department alerted the county health department about a possible influenza outbreak. The next evening, the fire chief was at home with his wife planning a cruise to Alaska when health officials called to tell him that Life Care patients were being tested for coronavirus.

Sanford put on his uniform and drove to work to pore over call logs with his team. They identified every firefighter who had gone to the nursing home in recent days.

Hours later, at 2 a.m., health officials told Sanford one of the Life Care tests had come back positive. He ordered some firefighters and police officers into quarantine for 14 days, which the CDC says is the virus’s incubation period.

Sanford and his wife canceled their Alaskan cruise, remembering that the illness had infected hundreds on the Diamond Princess cruise ship while it was quarantined at a port in Japan. Seven people died in that outbreak, but Kirkland was about to face even worse.

Later that morning, King County health officials announced the nation’s first confirmed death from the coronavirus: A man in his 50s died at Kirkland’s EvergreenHealth Medical Center.

Health officials said the man had not lived at Life Care, which is about two miles from the hospital. But by the end of the day, two people at the nursing home — a middle-aged employee and an elderly resident — had tested positive for the virus, they said, and more than 50 people linked to the nursing home had some form of respiratory illness.

Connolly and his wife, Jody, had returned from skiing with their older son when the babysitter mentioned the outbreak. They searched the Internet and recognized the Life Care sign in the news.

“That’s how we learned,” Connolly said.

Jody called her father, Jerry Wall, who knew nothing about the outbreak. Wall had moved into Life Care about a year ago after experiencing heart failure; Connolly said he was given months to live. But Wall thrived at Life Care. He loved the staff who helped him shave, he socialized with other residents, and he enjoyed the chicken pot pies for dinner.

After the positive tests, Wall was suddenly confined to his room. Some staff members had disappeared.

Two days passed before the couple heard anything from Life Care. Then an email from the center’s new executive director, Ellie Basham, landed in their inbox saying the center is “doing everything that the CDC and the State of Washington recommends.”

“Our residents and the care that they receive is our highest priority,” Basham wrote in an email to roughly 60 families just before 9 a.m. on Monday.

The next day, King County public health officials revealed that the man in his 50s hadn’t been the first death linked to covid-19. Two residents of Life Care — a woman in her 80s and a 54-year-old man — had died two days earlier, on Feb. 26, the day before the fire department alerted health officials that something was wrong.

By Wednesday, six residents of the Life Care Center were dead.

Speaking on behalf of a group of families, Connolly demanded that everyone in the facility undergo testing for the virus. They worried that the new director, who had been on the job just a few weeks, was overwhelmed by the spreading crisis and needed more help from the government.

A church had dropped off care packages of tissues and puzzles for the residents and chicken sandwiches for the staff. But Connolly had expected the government response to resemble the scene from the Steven Spielberg movie “E.T.,” when trained professionals descend in hazmat suits.

Concerned relatives emailed Jeffrey Duchin, the public health officer for Seattle and King County and a bespectacled, calming presence who frequently appears at press briefings. He acknowledged their distress during a news conference Wednesday, saying two county physicians and a team from the CDC had been deployed to the center to ensure that residents receive “the highest level of care.” They would test residents and staff for the coronavirus, he said.

But then Duchin spoke as if he were in a hospital room delivering difficult news.

“Remember that there is no specific treatment for this disease. There’s no preventive measure. Whether they test positive or negative, they will still go to a health-care facility because of their medical condition,” he said. “It’s good for us to know. But at this point we assume that if someone is in that facility, they likely have been infected or are at high risk for infection, and they’re being managed as if they are.”

Basham said the nursing home is monitoring staff and residents but has not been able to trace how the virus reached the facility.

“While we would like to understand how the virus entered our facility, right now our focus is on working to ensure a safe environment for our residents, families and associates,” she said in a statement late Wednesday that called the staffers who kept showing up to work “heroic.”

Seeking to reassure the families, Basham said she would assign each resident a “clinical representative” to reach out to them daily with updates.

But relatives struggled as the uncertainty dragged on. Some were afraid to leave their relatives at Life Care but didn’t have anywhere safe to put them. Others said their family members needed the specialized care, and rehab for strokes or broken bones. Residents worried they would spread the illness if they left.

Inside the nursing home, many patients were struggling, too.

Pat Herrick had last spoken with her 89-year-old mother, Elaine, on Sunday. Elaine had lived at the Life Care Center for the past seven years and loved the facility. She liked to hand out roses to the mothers, both residents and staff members, every Mother’s Day.

But she grew depressed because she wasn’t allowed to leave her room. Herrick tried to reach her mother on Monday but couldn’t get through. On Tuesday, she left a message with a nurse to see if she could connect them, again without luck. At 8 p.m., she tried again, and a nurse said they’d just put her mother to bed.

“It’s too late now,” Herrick said.

On Thursday morning at 3:30, she received a call to let her know that Elaine had passed away at the facility.

Hours later, she was on a phone call, sharing the news with Connolly. While they were chatting, she got another call. It was a nurse at Life Care who gave her daily updates on her mother’s condition.

“Unfortunately, she was calling to update me that my mother was fine. ‘She doesn’t have any symptoms. Her temperature is good,’ ” Herrick recalled the nurse saying.

Herrick wasn’t angry at the nurse.

“She was swamped. She was giving meds. She was doing temperatures,” Herrick said. “She somehow neglected to get all the information in the chart. That’s tragic and I also have great compassion for her humanity.”

Herrick, who was told her mother died of natural causes, wants the body tested for the virus.

Doctors gave Mike Weatherill the same cause of death for his 85-year-old mother on Wednesday.

Louise had seemed fine when they chatted Sunday. But by Monday, she wasn’t feeling well, and nurses at Life Care gave her antibiotics the next day, Weatherill said.

Early Wednesday morning, Louise became feverish. At 4 a.m., she was transferred to EvergreenHealth Medical Center, and she died two hours later. Weatherill only heard about his mother’s move to the hospital and her death an hour after she passed away. He said she died alone.

She was never tested for coronavirus.

“In my heart, I think she passed from the covid-19 virus,” Weatherill said, holding a picture of his mother in his hands while standing outside Life Care Center.

“She loved everybody. She raised chow chows. That was her greatest passion,” Weatherill said. He hopes to scatter her ashes at Mount St. Helens, about 100 miles south of Seattle.

The latest Life Care victim was not a resident, but a man in his 60s described by King County officials as a Life Care Center visitor. He died Thursday.

Those stories concern Bonnie Holstad, whose 73-year-old husband, Ken, arrived at Life Care Center for rehabilitation after recent hip surgery. On Wednesday, he was suffering from a persistent cough. She said his thinking had been muddled. That night, he was transported to a hospital.

But hospital workers called Holstad to say he wouldn’t be admitted because his symptoms were not acute, she said. Other medical facilities were unlikely to admit him, too, they told her, given he was a Life Care resident.

Holstad was given two options: bring Ken home or send him back to Life Care.

“He’s not walking well enough yet to come home,” Holstad said. “Our family was faced with a very difficult decision about sending him back here.”

Ken returned to Life Care.

“I’m fearful every single day he might develop more symptoms,” Holstad said.

She, like relatives of other Life Care patients, must check on her loved one from afar.

Resident Gene Campbell was admitted to Life Care on Feb. 21 for rehabilitation after a stroke landed him in EvergreenHealth Medical Center. He spent his 89th birthday on Tuesday inside.

When his sons — Todd, 59, and Charlie, 61 — came to visit the next day, an aide opened the blinds and helped their father into a chair near the window. Todd and Charlie stood in the cold, talking to him on the phone as they peered through the glass.

Gene Campbell seemed healthy and in good spirits. He was guided by a philosophy, to “deal with the hand you’re given.”

Charlie, a retired nurse, came back again the next day, bringing his mother for a visit. He asked Gene if he wanted a cheeseburger, and he said yes. Charlie planned to bring it to him this week, even if he had to leave it at the door.

But on Friday morning, the Campbell brothers rushed to Life Care after hearing that their father, who felt fine on Wednesday, had a cough and a slight fever. They went to his window, but he was not there. Staff told them that he had been taken to a hospital, and the brothers, with tears in their eyes, got back into their SUV to find him, fearing the worst.

On Saturday, Charlie said they received Gene’s covid-19 test result: It was positive.

Julie Tate contributed to this report. This story has been updated.