FRESNO, Calif. (KFSN) -- A fourth lawsuit is now on file against a Fresno heart surgeon. This time it's a wrongful death claim filed by a South Valley family.



The claim is that something went wrong during Gregory Riddle's heart surgery in 2011, something that killed him. His family's attorney tells Action News they're suing Dr. Pervaiz Chaudhry, and Community Regional Medical Center to find out what that something is.



Riddle, of Visalia, had a serious heart condition being treated in the South Valley before he turned to CRMC and his surgeon, Dr. Chaudhry, in Fresno. Riddle died in 2011 and according to his family's attorney they didn't know his death was being investigated by the California Medical Board until a phone call last March.



"They were really unaware of any negligence or malpractice, but obviously that gave rise to some suspicion," Jeff Mitchell said.



Mitchell, a Bay Area-based medical malpractice attorney, says there's too much information missing from Riddle's files to figure out what went wrong. "We're trying to find answers and the best way and the only way sometimes to find answers in these situations is to file lawsuits," he said.



Riddle's family says he was a talented, funny, compassionate man. They declined an interview, but said in a statement to Action News "We hope that we are able to find satisfactory answers about the quality of care that he received. We know that our dad is proud of us for searching for the truth in the circumstances surrounding his death."



"I think they're having a hard time coping with his not being around anymore frankly," Mitchell said.



Mitchell has filed three other lawsuits against Dr. Chaudhry and the hospital.



Action News reported in January that Silvino Perez suffered brain damage following his heart surgery performed by Dr. Chaudhry at CRMC.



Perez is now left in a vegetative state.



The allegations in this case are that Dr. Chaudhry walked out of surgery before it was over, leaving a physician's assistant to close the patient's chest, resulting in the patient's complications.



This is the only open case that Chaudhry's legal team has filed paperwork completely denying all allegations.



Mitchell says there's clearly a problem with Chaudhry's practices. "The hospital was well aware of this but they were basically pushing this stuff under the rug because he was a person of influence and makes the hospital a tremendous amount of money," he said.



The hospital said in an emailed statement to Action News: "At this point, we have not been served so we cannot comment on any allegations it may contain."



Dr. Chaudhry says he's not able to comment about the case at this point. His attorney has not returned our phone calls for comment.