Four employees of a South Florida nursing home where a dozen people died amid sweltering heat in September 2017 were arrested and charged with manslaughter and tampering with evidence, police said Tuesday.

In announcing the charges, police officials assailed the four employees — the facility’s administrator and three nurses — and said the deaths were all avoidable and due to their behavior.

“This was a terrible tragedy that never should have happened,” said Chris O’Brien, chief of police in Hollywood, Fla.

The charges came nearly two years after the deaths at the Rehabilitation Center at Hollywood Hills, a nursing home not far from Fort Lauderdale, which overheated after Hurricane Irma swept through the region with powerful rain and wind.

The deaths of the patients — who ranged in age from 57 to 99, with the oldest victim a few weeks away from turning 100 — sparked intense outrage as well as a round of finger-pointing over who was responsible and what happened. During hurricanes and other disasters, power outages are an acute threat to the elderly, who tend to be more susceptible to heat-related illnesses.

Days after Irma battered South Florida, the nursing home’s air conditioning began to fail, and temperatures began to climb. Emergency personnel began responding to the nursing home early on Sept. 13, 2017, and eventually evacuated the entire facility.

A dozen patients died — some days and weeks later — and the medical examiner concluded that all of the deaths were homicides caused by heat exposure. Authorities have said some patients had body temperatures as high as 109.9 degrees.

O’Brien said during a news briefing announcing the criminal charges that the relatives of the victims “should not have lost their loved ones in this way.” He added: “They placed their faith and trust in the Rehabilitation Center of Hollywood Hills . . . and that trust was betrayed. They have been living an absolute nightmare.”

O’Brien announced the arrests as Florida residents were watching a tropical storm forecasters say might approach the state in the coming days.

Among those charged were Jorge Carballo, 61, the administrator, and Sergo Colin, 45, the night shift’s nursing supervisor. Each man was charged with 12 counts of aggravated manslaughter, one for each of the victims.

Tamika Tory Miller, 31, and Althia Kenesha Meggie, 36, both nurses, were charged with manslaughter as well as tampering with evidence in the case, according to the arrest warrants. Miller was charged with six counts of aggravated manslaughter and three counts of tampering with or fabricating evidence in connection with patient medical records. Meggie was charged with two counts of aggravated manslaughter and two counts of tampering or fabricating medical record evidence.

James A. Cobb Jr., an attorney for Carballo, described his reaction to the charges as “complete shock and horror.” Cobb pointed to the manslaughter counts and said Carballo was particularly distressed by “the notion that he didn’t care for these people,” noting that the administrator had family members — his wife’s father and uncle — residing in the facility at the time.

“How can he have callous indifference to the safety of his own family?” Cobb said. “It’s a totally misplaced charge.”

Cobb said he felt Carballo and the others were charged as scapegoats by the government for “their own mistakes, which are legion, and to place the blame as far down the food chain as they can possibly go.”

Other attorneys did not immediately respond to requests for comment Tuesday.

All of the crimes are felonies, police said. They did not elaborate in the warrants or the news conference about the evidence tampering charges, but state officials have said that nursing home officials added entries to medical records later to give a false depiction of what happened.

Hollywood Police Maj. Steven Bolger, speaking about the investigation, said “the actions and inactions” of the people charged “led to the deaths of these patients.” Bolger also said the investigation is ongoing and that more arrests are expected, although he did not specify who else might face charges.

Nursing home executives have said they contacted Rick Scott, the state’s then-governor, and Florida Power and Light, the utility giant, pleading for help. State and local authorities, though, disputed parts of those accounts and criticized what they called “egregious” failures at the facility. The Agency for Health Care Administration in Florida said the nursing home waited too long to call 911 and then was too slow in evacuating patients.

Scott, now a Republican senator representing Florida, said in a statement that he was “glad these individuals are being held accountable.” In a statement Tuesday, Florida Power and Light said that part of the nursing home still had power, adding that “there was a hospital with power across the parking lot from this facility, and the nursing home was required to have a permanently installed, operational generator.”

An administrative law judge who recommended revoking the nursing home’s license noted several issues that combined to cause the conditions in September 2017, including the power outages, “the lack of prioritization and a timely response” by the power company, and insufficient backup cooling options. But the judge concluded that “ultimately the patients were dependent on Hollywood Hills to recognize the danger and to keep them safe.”