Republican gubernatorial candidate Bill Simon expressed "sincere regret" Thursday over his now-disproven allegation that Democratic incumbent Gray Davis illegally accepted a campaign check in the state Capitol.

Simon did not apologize to Davis or directly accept responsibility for making the false claim.

"I find it necessary to express to everyone my sincere regret for the way this matter was handled," Simon said in a Los Angeles speech. "You may have seen my last commercial where I say I am not perfect, and that's indeed true. And now we know of course my campaign is not perfect."

Simon continued to defend himself for making the allegation after a debate with Davis on Monday. The claim was based on photographs released by California Organization of Police and Sheriffs.

The photos showed Davis, then lieutenant governor, taking a campaign contribution. COPS and Simon contended the transfer took place in Davis' Capitol office in Sacramento. It is illegal to give or receive a campaign contribution in a state building.

It became clear almost immediately, however, that the pictures were not taken in the Capitol, and the law enforcement group later retracted its allegation.

Davis had called on Simon to drop out of the race. Simon's aides said he'll continue to run.

The governor's aides said Simon's regret wasn't enough.

"Bill Simon, as has been the case throughout this campaign, is trying to weasel his way out of accepting responsibility for his actions," said Davis campaign press secretary Roger Salazar. "He owes Gray Davis a direct apology for accusing him of committing a crime. We expect nothing less."

The Davis camp disclosed Wednesday that the photos were taken at a fund-raising breakfast in the Santa Monica home of Davis backer Bruce Karatz, chairman and CEO of KB Home. Karatz no longer owns the house but a spokesman for KB Home confirmed it was the setting of the photo.

Al Angele, the former executive director of COPS who was shown giving Davis a check in the photograph, demanded an apology Thursday from Simon and the group.

His attorney said he was considering legal action against Simon and COPS.

COPS did apologize to Angele and Simon late Wednesday. The group had yet to provide the written, personal apology Angele demanded.

Ed Rollins, Simon's senior strategist, apologized to both Davis and Simon on Thursday and took the blame for the episode.

He said the campaign didn't get a good look at the photos until after COPS released them Tuesday, and Simon was not supposed to tell reporters he had evidence.

"Some people on our campaign thought this was a silver bullet. I think it was a bullet, I think we put it in a gun wrong and shot ourselves in the head," Rollins said.