Several Johns Hopkins All Children’s Hospital staff have resigned following a news report that revealed startling increases in the mortality rates in the pediatric cardiology program.

CEO Dr. Jonathan Ellen, Vice President Jackie Crain, and deputy director of the All Children’s Heart Institute, Dr. Jeffrey Jacobs, are among the All Children’s Hospital staff who resigned. Dr. Paul Colombani also reportedly stepped down from his position as the chair of the surgery department, but will “continue in a clinical capacity,” according to a Johns Hopkins statement to the Tampa Bay Times.

The sudden resignation of All Children’s Hospital staff members was prompted by a Tampa Bay Times investigation. The investigation revealed that the mortality rate of the Johns Hopkins hospital’s heart institute in Florida had tripled between 2015 and 2017.

Columbani and Crain declined to comment when prompted by the Times, and Ellen did not return requests for comment.

However, the attorney for Jacobs, who was co director of the institute at the time of the mortality increases, told the Times that the doctor had been “forced out of his position and prevented from speaking out on his own behalf.”

“In performing more than 4,250 operations during his highly-regarded career that spanned more than two decades at All Children’s Hospital, Dr. Jeffrey Jacobs devoted his professional career to the care of very sick children. … He looks forward to the opportunity to set the public record straight and defend himself from those who have not been given the facts,” the statement said, according to the Tampa Bay Times.

According to the investigation, the increase in mortality came after at least eight All Children’s Hospital staff spoke with their supervisors regarding problems in the pediatric cardiology program. Several physician assistants reportedly spoke directly with Columbani while he was chief of the surgery department about their concerns regarding surgeries performed by Jacobs and Dr. Tom Karl.

In June 2016, a doctor who had handled many of the most complex pediatric cardiology surgeries was reportedly pushed out of the program. Jacobs and Karl allegedly took over the surgeries after the doctor left.

Over the following 18 months, at least 11 children reportedly died after their pediatric cardiology surgeries. This increase reportedly continued even as the hospital began turning away more complex cases.

Changes made to the All Children’s Hospital staff are not the only changes to be made by the hospital. The board of Johns Hopkins Medicine, which is responsible for All Children’s Hospital in St. Petersburg, Fla., has reportedly commissioned an external review of the hospital’s pediatric cardiology program.

“We will share the lessons learned from that review to ensure that Johns Hopkins, Johns Hopkins All Children’s and other hospitals around the country can learn from and avoid the mistakes that were made,” the health system’s statement said. “Losing a child is something no family should have to endure, and we are committed to learning everything we can about what happened at the Heart Institute, including a top-to-bottom evaluation of its leadership and key processes. The events described in recent news reports are unacceptable.”