The sudden death of Susan Fuller's mother has taken a lifelong toll on her family. Lola Ollerton went to a hospital for spinal surgery and never came home.
"There was no reason that she should bleed to death. I think about her every day," Fuller said.
Ollerton died in 2006, after a surgical procedure performed by Dr. David Greene.
Her family checked his background with the Arizona Medical Board beforehand.
"There were no complaints against him," Fuller said.
Ironically, Fuller and her family ended up filing the first.
The family later learned there were 18 peer review complaints filed against Greene at the hospital where he performed surgery.
During the next two years, at least three more people bled to death while in Greene's care and others suffered permanent injuries, it was discovered.
The medical board found Greene guilty of unprofessional conduct and gross negligence, and revoked his license in 2008.
"If it had not been for the Board of Medical Examiners, he would not have been brought to justice," Fuller said.
She said she believes the Arizona Medical Board did its job.
CBS 5 Investigate's months-long investigation reveals others aren't so confident.
"Their mission statement states that they're supposed to protect the public and hold doctors accountable," said Shawn Thelen of Lake Mohave.
Thelen filed a complaint against a doctor who treated her husband, Lonnie, after he vomited blood after a procedure.
Records show the doctor said he performed an upper G-I, found Lonnie Thelen's lap band had slipped and after a couple of blood transfusions, sent him home.
"Sunday morning, he gets up and passes out," Shawn Thelen said.
Lonnie Thelen was rushed to another hospital, where he was diagnosed with severe gastric ulcers and needed seven blood transfusions.
Shawn Thelen thought she might be going home without her husband. "He was near imminent death," Shawn Thelen said
Doctors at the second hospital said Lonnie Thelen's lap band had not slipped. It was still stitched perfectly in place.
"He misdiagnosed it. He didn't do what he said he did and nearly killed my husband," Shawn Thelen said of the first doctor.
Shawn Thelen filed a complaint with the Arizona Medical Board and she said no investigators called her to talk about it. Four months later, she said, her complaint was dismissed by the board, who cited there was no violation of Arizona's Medical Practice Act.
"He didn't even get a reprimand," Shawn Thelen said.
A public records request revealed at least 18 complaints filed with the medical board against that same doctor. CBS 5 Investigates spoke with five of those patients.
The board dismissed all but one of those complaints, for which they issued a nondisciplinary advisory letter.
The Arizona Medical Board receives around 1,000 complaints against doctors every year. The vast majority are found to be without merit.
The rest result in disciplinary or nondisciplinary actions, when a deviation from the standard of care is found by the board.
CBS 5 Investigates compiled data from the past five years and found the amount of disciplinary actions taken against doctors has dropped dramatically.
In fiscal year 2009, the board issued 128 disciplinary actions compared with only 50 in 2013, a 61 percent decline.
In that same time frame, the investigation reveals a sharp drop in the number of nondisciplinary advisory letters from 229 to 117, down 49 percent.
In those five years, there was an increase in Arizona's licensed doctors by 10 percent.
Sherry Petta filed two complaints against her doctors after two surgeries left her scarred for life.
In her first complaint the board found no violation in the standard of care and dismissed the complaint.
"There's some things about this that I will never ... I will never get over," Petta said.
In her second complaint, an investigation by the state ombudsman found a clear violation of Arizona statute by the doctors.
Nevertheless, the medical board dismissed the complaint.
"I've lost a lot of faith in the system," Petta said.
CBS 5 Investigates discovered that the medical board has at least 11 complaints against each of those doctors.
Another complaint against them came from a patient who did not want to reveal her identity.
"It's absolutely impacted me in a severe way for the rest of my life," the woman told CBS 5 Investigates.
She said the board hired an outside medical consultant to investigate her complaint. That person reported violations by the doctor and recommended discipline.
The board then hired a second outside medical consultant who reached the same conclusions, again recommending discipline.
Instead, the medical board issued a nondisciplinary advisory letter.
"There's a right time and place to protect doctors, but when the evidence is saying there's something wrong here and the expert witnesses are saying there is something wrong here, then they should be listening," said the former patient.
CBS 5 Investigates asked the board how much weight is given to the recommendation of outside medical consultants.
Lloyd Vest, the new executive director, wrote: "The consultant's opinion is the primary consideration in standard of care cases."
CBS 5 Investigates made several requests for an on-camera interview with Vest, even showing up to the board in person. He declined to do a formal interview but offered to give CBS 5 Investigates information for the story.
He has been with the board for only two months.
The board has been criticized in the past for simply issuing advisory letters when actual discipline was warranted. They used to be found under doctors' profiles on the board's website.
In 2011, then-Arizona lawmaker Matt Heinz sponsored a bill to get advisory letters off the board's website.
In the board's minutes, the chief medical consultant said it could be argued they "compromised a doctor's livelihood."
Heinz was a doctor himself.
Now, if a member of the public wants to find out if the board is keeping an eye on a certain doctor, they must call or visit the board in person.
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