Two doctors and a consultant who reviewed the autopsy on San Francisco Public Defender Jeff Adachi concluded his death was natural — rather than drug induced, as the city medical examiner found in March, the Public Defender’s office said Wednesday.

The office, in announcing the findings, slammed the medical examiner’s office as “dysfunctional” and “untrustworthy” and questioned why the medical examiner ruled Adachi’s death as accidental.

In a news release, the public defender’s office said the three medical and forensic experts hired by Adachi family attorney and friend, Robert Chan, conducted “independent reviews” of the autopsy and found Adachi died from “sudden cardiac arrhythmia and acute myocardial infraction (sic) due to coronary artery disease” and that his death was “natural.”

The San Francisco Medical Examiner’s office determined in March that a mixture of cocaine and alcohol caused Adachi’s already-damaged heart to fail.

The challenge to the Medical Examiner’s autopsy is the latest twist in the aftermath of Adachi’s death, which has been mired in controversy since the 59-year-old suddenly collapsed in a Telegraph Hill apartment Feb. 22.

Adachi, who served as the city’s public defender for 17 years, has been widely praised as a relentless fighter for the disenfranchised. He was regarded as a criminal justice reformer and watchdog of the city’s Police Department, which with he often publicly sparred.

The day after he died, city officials — including Mayor London Breed, members of the Board of Supervisors and employees of the Public Defender’s office — were furious over a police report leaked to the news media that revealed salacious details surrounding Adachi’s final moments. Some saw the leak as an attempt by police who didn’t like Adachi to tarnish his legacy.

A few months later, a 25-page autopsy report from the Medical Examiner’s included a toxicology report that found a trace of cocaine, alcohol, and sedatives in his system.

After reading the autopsy, Chan told The Chronicle Wednesday night, he felt “something wasn’t right” with the report. What stuck out to him in particular, he said, was the small amounts of alcohol, cocaine, as well as benzodiazepines found in Adachi’s system.

Chan said he spoke to members of the Public Defender’s office who were similarly suspicious about the report, and were supportive of an independent review. Chan said he personally hired three experts — Dr. Dylan V. Miller, an expert in cardiovascular and autopsy pathology, Dr. Nikolas Lemos, a forensic toxicologist and James L. Norris, a consultant in forensic science — to conduct the review.

“We all agreed someone should do it,” he said, referring to the independent review. “There is a lot that needs to be explained.”

The Public Defender’s office was not involved in the hiring of the experts, said spokeswoman Valerie Ibarra.

According to the release, the experts said that the sample used in the toxicology report was “unreliable.” Lemos said in the release that the drug results drawn from Mr. Adachi’s central blood were “toxicologically insignificant.”

Lemos, the former chief toxicologist with the San Francisco Medical Examiner’s office, settled a lawsuit against the city last fall for $100,000 involving an “employment dispute.”

The Medical Examiners Office defended its report Wednesday evening.

“The Office of the Chief Medical Examiner routinely conducts autopsies to investigate deaths. Forensic pathologists sign off on the cause and manner of death, and their reports speak for themselves,” the Office of the Chief Medical Examiner said in a statement.

The Public Defender’s office also suggested a potential conflict of interest involving the Medical Examiner's Director of Operations, Christopher Wirowek.

Shortly before Adachi died, he accused Wirowek of lying about the office’s accreditation and called for his termination after he failed to correct what he called “false statements.”

Wirowek could not immediately be reached for comment.

“Losing Jeff was a terrible tragedy, and his family has suffered so much,” Chan said. “It provides peace of mind that we did know Jeff better than the circumstances of his death have suggested.”

A previous version of this story misspelled the name of attorney Robert Chan.

Chronicle staff writer Dominic Fracassa contributed to this report.

Trisha Thadani is a San Francisco Chronicle staff writer. Email: tthadani@sfchronicle.com Twitter: @TrishaThadani