An autopsy has found that Dennis McNell, brother of two stockbrokers whose allegations led to the resignation of CIA spymaster Max Hugel, died of natural causes.

The autopsy, ordered due to questions of foul play, "did not uncover evidence of a ruptured spleen or any other internal trauma," New York City Medical Examiner Elliot Gross and Queens District Attorney John J. Santucci said yesterday.

Santucci reopened an investigation of the death after Gross wrote him saying McNell might have died of a "possible ruptured spleen," an injury frequently caused by a beating. The autopsy was performed Thursday in Augusta, Maine, after two days of efforts by the McNell family to block the exhumation.

McNell, 41, died June 1 in Queens after returning home from jogging and complaining of pain. He was rushed to a hospital. A physican said at the time that McNell died of natural causes due to cirrhosis of the liver, hepatitis and diabetes. No autopsy was done before burial in Forest Hills Cemetery near Bridgton, Maine.

Questions about the death surfaced after The Washington Post published on July 14 allegations by his brothers, Samuel and Thomas, that they were involved in stock market manipulations with the CIA's Hugel in the mid-1970s. Hugel resigned as director of CIA covert operations that same day. Samuel and Thomas McNell then disappeared, along with $3.3 million in assets from two companies they controlled, Triad Energy Corp. and Everest Petroleum Co.

Stanley Kielmar, a business associate of the McNells, later said that Dennis McNell had been abducted and beaten twice last year as "a warning for the McNells to cool it with Hugel."

The autopsy, conducted by Gross and Maine's chief medical examiner, Henry Ryan, found nothing to contradict the findings made at the time of Dennis McNell's death. But Gross and Santucci said routine laboratory test are under way in Maine, with results expected next week.