City medical officials declined to sign off on a police officer's death certificate this week after a hospice doctor declared that his fatal stomach cancer was caused by World Trade Center toxins, then angered his family by asking to examine his body on the day of the wake.

George Wong, who retired from the New York Police Department in 2006, was 48 when he died on March 24. His wake was about to get under way Monday when his family received a call from the office of the city medical examiner asking for permission to do an autopsy.

Normally, the city doesn't investigate cancer deaths, but it got involved after health department workers noticed that a doctor who had provided end-of-life care for Wong, Lyla Correoso, had filled out paperwork attributing his cancer to toxic exposure in the aftermath of the Sept. 11, 2001, attacks.

The New York Post reported Wednesday that the city's refusal to sign off on a death certificate without further investigation infuriated Wong's brother. He told the newspaper that city officials retrieved the body from a funeral home at 10 p.m. Monday, after the wake ended. The family refused permission for an autopsy, so authorities performed an external examination before releasing the body Tuesday.

"They totally disrespected our family. Now my brother can't even rest in peace because of this," Howard Wong said.

The episode delayed a planned cremation and memorial service, he said.

"I feel horrible," he said. "My mother is crying."

A spokeswoman for the medical examiner's office, Ellen Borakove, said the inquiry was part of a broad effort to determine whether people exposed to toxic dust from the destroyed twin towers are more likely to get deadly illnesses.

"The last thing we would want to do is further upset, or cause grief, to any family," she said.

Researchers have found that people who inhaled trade center dust have higher rates of asthma and other respiratory system problems, but there has been scant scientific evidence of a cancer link.

Experts say more research is needed, in part because some types of cancer develop slowly over many years before they can be detected.

Under city policy, the medical examiner's office routinely conducts inquiries when a death is suspected of being due to something other than natural causes, like a poisoning or exposure to a workplace toxin.

To date, the city's chief medical examiner, Charles Hirsh, has been cautious about linking deaths to the environmental aftermath of the 9/11 attacks. Most famously, he ruled that James Zadroga, a police officer whose mysterious health problems had been chronicled widely by journalists, was killed by prescription drug abuse, not particles from the towers.

Correoso, Wong's doctor, did not immediately respond to an email Wednesday, but she told the Post she stood by her determination that 9/11 had a role in his death.

Wong retired from the department on a regular pension in 2006, but his file was reopened after he was later diagnosed with cancer. Under New York law, law enforcement officers who have cancer, and who spent time in the trade center area during certain time periods after the attacks, are presumed to have gotten the disease on the job. On those grounds, Wong was awarded a more lucrative disability pension in 2010.

His family could now potentially qualify to receive additional benefits if his death is classified as having been the result of an injury sustained on duty. That decision, however, will be made by a police department medical board and city police pension fund board, not the medical examiner's office.