Pennsylvania's top prosecutor has opened criminal investigations into several nursing homes amid a coronavirus outbreak that has killed 2,600 residents of nursing homes and other facilities that care for older adults, more than two-thirds of the state’s death toll, his office announced Tuesday.

The attorney general's office did not say how many facilities it is investigating, or reveal their names or provide any other details about the specific allegations. In general, the attorney general's office has jurisdiction in manners of criminal neglect.

“We will hold nursing facilities and caretakers criminally accountable if they fail to properly provide care to our loved ones," Attorney General Josh Shapiro said in a written statement. “While we salute and appreciate nursing home staff on the front lines during this pandemic, we will not tolerate those who mistreat our seniors and break the law.”

He said “active criminal investigations" are underway.

Adam Marles, president and CEO of LeadingAge PA, which represents hundreds of nonprofit nursing homes statewide, said: "We will continue to support our members, their front line workers and residents during any investigation.”

Long-term care facilities have struggled for months to contain the coronavirus. The virus has sickened about 12,000 residents of 540 nursing and personal care homes, accounting for about one-fifth of the state’s confirmed infections, according to the Health Department. The National Guard has been deployed to more than a dozen homes with severe outbreaks.

One of the worst is at Brighton Rehabilitation and Wellness Center in Beaver County, near the Ohio border, where dozens of people have died and the Health Department has installed a temporary manager.

Shapiro's involvement comes as the administration of Gov. Tom Wolf — itself under fire for its management of the nursing home crisis — rolls out a plan to begin universal coronavirus testing at nursing homes and other facilities that provide elder care.

Nursing homes have long said they haven’t been able to do enough diagnostic testing to quickly identify and isolate patients and staff who have the virus. They say testing is critical because people can spread the virus without knowing they have it.

The new Health Department guidance encourages facilities where COVID-19 is already present to test all residents and staff, whether or not they have symptoms of the disease. Nursing homes without any known infections of the virus should test 20% of residents weekly, the guidance says. Testing will be required for residents returning to a nursing home from the hospital.

The health secretary, Dr. Rachel Levine, said Tuesday that shortages of testing supplies had previously made surveillance testing at nursing homes impossible. But she said there are now sufficient numbers of tests to allow for such testing of every resident and staff member. The testing will serve as an early-warning system, she said.

“This effort will give us a clearer picture of the extent of outbreaks in nursing homes, and a head start at stopping them,” she said.

In the state Senate, senators unanimously approved legislation to direct $507 million from Pennsylvania’s $4 billion share of emergency federal aid to help nursing homes, home care services and other services for the elderly absorb coronavirus-related costs.

The House of Representatives could take up the bill as early as Thursday, a spokesman for House Majority Leader Bryan Cutler, R-Lancaster, said.

Independent Sen. John Yudichak of Luzerne County welcomed universal testing but said the Wolf administration has been far too slow to act.

“While other states were ramping up testing in nursing homes and were transparent in granting access to the public about COVID-19 deaths occurring in those facilities, Pennsylvania’s nursing homes had been forgotten about in our war against COVID-19," he said in a written statement. “Nine weeks without a robust plan is far too long.”

The Health Department, meanwhile, reported more than 800 new virus infections on Tuesday, and 75 new deaths.

Overall, the virus has sickened about 58,000 people. The statewide death toll has reached 3,806.

In other Pennsylvania pandemic developments:

COVID-19 Drug

The state Department of Health said Tuesday that it has received 1,200 doses of a drug with promise in alleviating COVID-19 and is sending it to 51 hospitals in Pennsylvania.

The hospitals that will receive the first shipments of remdesivir were determined based on the number of COVID-19 patients and the severity of those patients' illnesses, the department said.

Remdesivir is given intravenously once a day for up to 10 days, the department said.

The Food and Drug Administration issued an emergency use authorization for the drug after preliminary results from a government-sponsored study showed that remdesivir shortened the time to recovery by 31%, or about four days on average, for hospitalized COVID-19 patients.

The drug may also help avert deaths, but that effect is not yet large enough for scientists to know for sure.

No drugs are currently FDA-approved for treating COVID-19, and remdesivir will still need formal approval. The drug does have side effects, including potential liver inflammation.

Nonetheless, the National Institutes of Health’s Dr. Anthony Fauci has said remdesivir would become a new standard of care for severely ill COVID-19 patients.

National Guard

The Pennsylvania National Guard says some personnel are sick with COVID-19, including those who contracted the virus that causes the disease while deployed.

Guard spokesman Lt. Col. Keith Hickox said his agency has helped 13 long-term care facilities in response to the pandemic.

It’s nearly impossible to know how the Guard troops became sick, he said, describing the total number as relatively low, considering what they have been doing.

Hickox said that medical staffers have helped out at nine facilities and that training has been done at five of them. The Guard is not disclosing the list of nursing homes and similar places they have been assisting.

The effort has involved more than 180 medical workers, mostly helping with comparatively less sick residents, so the facilities’ own medical staff can focus where patients need it the most.

Others with the Guard are providing logistical help, cleaning, and training of facility staffers in the use of personal protective gear and decontamination, Hickox said.

All members are quarantined and tested when high-risk missions are completed, he said.