G. Steven Pigeon’s central role in last week’s Republican coup in the State Senate is coming back to haunt the Democratic operative on the home front.

Mayor Byron W. Brown on Tuesday abruptly canceled a major fundraiser for his re-election campaign after The Buffalo News raised questions about Pigeon’s connection to the event.

“We officially contacted Steve and canceled it,” Deputy Mayor Steven M. Casey said. “We are very concerned about the events in Albany.”

Pigeon, chief architect of B. Thomas Golisano’s attempt to remove the Senate’s Democratic leaders, was to hold the event June 25 in his Admiral’s Walk home on the Buffalo waterfront. The fundraiser, with tickets at $500 and $1,000 each, was to have included former Buffalo Comptroller Anthony R. Nanula and businessman Jon Williams as co-hosts.

But questions began surfacing about Pigeon’s role in the coup, which overthrew the Democratic majority and produced a 31-31 tie in the Senate. For almost five years before becoming mayor, Brown had been a senator and part of the Democratic caucus overthrown in last week’s events.

Pigeon, the former Erie County Democratic chairman, said he “fully understands.”

“I support the mayor and am not about to allow my political enemies to try and interject an issue that has no relevance,” he said late Tuesday.

When first questioned about the fundraiser Tuesday, Casey said he had not thought about the event and was not commenting, other than to note that “conversations” needed to be devoted to the subject. He later conferred with Brown and said the decision was reached to cancel.

Casey noted that the fundraiser had been scheduled before last week’s coup, in which Pigeon served as chief strategist on behalf of Golisano, the Buffalo Sabres owner who recently announced he was becoming a Florida resident because of New York’s high taxes. They helped to orchestrate the switch of two New York City Democrats to the GOP caucus.

One of them — Sen. Hiram Monserrate of Queens — later returned to the Democratic caucus, causing the tie and the legislative gridlock.

Leonard R. Lenihan, chairman of the Erie County Democratic Party, said he was not surprised that Pigeon would raise funds for Brown.

“They’re very close,” said Lenihan, whose organization has remained neutral in the mayoral race. But he acknowledged Pigeon’s role on behalf of Albany Republicans, saying, “Steve proved not to be one of the world’s greatest Democrats last week.”