As the mayoral campaign has heated up in recent days with a flurry of charges and countercharges, the two campaigns have been careful to use surrogates to make their more explosive accusations.

Today, Mr. Thompson said the new information vindicated the most explosive accusation of his inquiry.

"Now, all of that information is almost 100 percent," said a former law-enforcement official who processed some of the most explosive accusations against Mexican officials, politicians and businessmen.

A draft report for the Republican senators investigating campaign financing describes widespread improper Democratic fund-raising in 1996 but has yet to substantiate the explosive accusation that China had a plan to meddle in that year's elections.

The meeting was called, he said, after it became clear that The New York Times would not publish an article about the book because it could not corroborate the book's more explosive accusations.

The most explosive accusation, which has never been backed up by more than Mr. Salone's words, is that Mr. McCaskell helped dispose of the gun used to kill Officer Byrne.

On the most explosive accusation explored at the Senate hearings, the Republicans could only point to "strong circumstantial evidence" that China steered money into the Democratic campaign.

In a relentlessly negative debate yesterday, Andrew M. Cuomo leveled an explosive accusation against his opponent, Jeanine F. Pirro.

Why such a potentially explosive accusation smoldered in the Senate for weeks, then burst into the national press, has now emerged as a central issue.

For the regulatory community, the most explosive accusation may be the claim that Mr. Grasso knew of fraud and did not act on it.