A veteran New Jersey political consultant who was among dozens arrested in a huge corruption sweep last week was found dead in his Jersey City apartment on Tuesday, the same day that one of three mayors charged in the case resigned.

The circumstances surrounding the death of the consultant, Jack M. Shaw, are “suspicious,” said Edward J. DeFazio, the Hudson County prosecutor. He said it did not appear to be a homicide. “It could be natural, it could be accidental, it could be suicide,” he said, refusing to elaborate. An autopsy is set for Wednesday.

His death, reported by a companion to the authorities at 5:17 p.m., came hours after Dennis Elwell, the mayor of Secaucus, stepped down, becoming the first elected official to quit after being charged in the sprawling political corruption case.

Mr. Shaw, 61, once an adviser to some of New Jersey’s most influential Democrats, more recently worked mainly for developers doing business in Hudson County. A top client was Metrovest Equities, developer of the Beacon, a 10-building apartment complex on the site of the former Jersey City Medical Center.