The Ohio hospital where a doctor is accused of ordering fatal doses of fentanyl to near-death patients said Thursday that three patients died even after the hospital was initially notified about the physician.

In addition, officials at the Mount Carmel Health System in Columbus said it had found seven more cases in which patients of Dr. William Husel were given "excessive doses of pain medication," bringing the total number of people affected to 34.

The latest revelations come as the hospital conducts an investigation into how 27 patients treated by Husel in the intensive care unit were apparently given high doses of painkillers before they died, and how he was able to order those doses without being stopped. The hospital said last week that Husel was fired and that it had removed 20 employees from patient care pending further review.

"These events are heartbreaking. We continue to investigate and learn more about these patients' cases," the health system's president and CEO, Ed Lamb, said in a statement through the hospital. "As we learn more, we will share our findings with each affected family. We are committed to being open and honest about what happened and what we are doing to ensure it never happens again."

The related patient deaths occurred from 2015 to 2018, officials said. The hospital received a formal report related to Husel on Oct. 25 of last year, but "based on what we learned about that report, we should have begun a more expedited process to investigate and consider immediate removal of Dr. Husel from patient care at that time," it added.

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Husel, 43, was removed on Nov. 21, but the hospital said it is aware of three deaths occurring while he was still working.

The majority of the patients died at Mount Carmel's primary care hospital known as Mount Carmel West in Columbus, although at least one case occurred at Mount Carmel St. Ann's hospital in Westerville.

In the newest cases that were reviewed involving patients of Husel's, the hospital system said that in six of them, the patients received "excessive doses that went beyond providing comfort but were likely not the cause of their deaths."

In the seventh case, however, "one of the patients received an excessive and potentially fatal dose," the hospital said.

Dr William Husel WCMH

At least four lawsuits have been filed against Husel and the hospital for wrongful death and negligence.

In one suit, the family of Janet Kavanaugh, 79, said she had received a "lethal dose" of fentanyl — 1,000 micrograms — through her IV. She was pronounced dead 18 minutes later.

Gerry Leeseberg, a lawyer who filed the suit for Kavanaugh's estate, said she had not consented to being given the high dose of fentanyl, nor was he aware that she had ever previously been given that drug for pain relief.

Patients who were treated by Husel were taken to the hospital's ICU for a variety of reasons, including respiratory problems or an infection and gallstones, according to the lawsuits. Some of the families said their loved ones were not terminally ill and that they would have questioned the use of medication as part of any end-of-life treatment.

"We're concerned some of these families were misled into granting a do-not-resuscitate order," Leeseberg said Thursday.

The Franklin County Prosecutor's Office said it is investigating allegations in the cases along with the Columbus police's homicide unit, but no formal charges have been made.

NBC News has been unable to reach Husel for comment and it's unclear if he has an attorney. Phone numbers linked to him weren't accepting calls.

The hospital said it is continuing to investigate whether Husel ordered excessive doses of medication when other options were available and if families who requested that lifesaving measures not be taken were properly informed by staff.