NORTH COUNTY --- A neighbor of Republican 50th District Rep. Brian Bilbray said Thursday that he was subpoenaed to testify before a San Diego County grand jury in August and spent about an hour and a half answering questions about whether Bilbray lived in his Carlsbad neighborhood.

Meanwhile, an official with the Republican Party of San Diego County has asked for an investigation into Democratic candidate Francine Busby's alleged use of illegal immigrants in her campaign.

Speculation has swirled around the Bilbray's residence issue for days, with Democrats and Busby's campaign claiming they had received calls from several of Bilbray's Carlsbad neighbors, saying they had been called to testify before a grand jury investigating the congressman's residence.

The allegations that Bilbray was not living where he said he was first surfaced in May, just weeks before a special election to pick a temporary replacement for the seat formerly held by the now-imprisoned Randy "Duke" Cunningham. The Vietnam War ace pleaded guilty to bribery and tax evasion late last year and is now serving an eight-year, four-month prison sentence.

On a voter registration form that Bilbray signed in June 2005 and his statement of candidacy, which he signed in February, he lists his official residence as Carlsbad. His mother owns the home and Bilbray has said that he moved into the house in mid-2005 to help care for the woman, who uses a wheelchair.

However, because he has three homes, one in Carlsbad, one in Imperial Beach and one in Virginia -- and on different documents has claimed each of them as his residence -- Democrats called on the district attorney's office in May "to investigate whether Mr. Bilbray committed perjury or voter fraud."

The U.S. Constitution does not require that a member of Congress live in the same district he or she is representing, but they must live in the same state.

Reached Thursday night, Bilbray said that he "absolutely" has not been called to testify before a grand jury and has no knowledge as to whether such an investigation is ongoing. He attributed the allegations to a last-minute campaign smear.

"It's like who can race to the bottom the fastest without talking about the issues," he said.

A spokesman for Bilbray sent to the North County Times on Thursday a copy of a letter addressed to San Diego County District Attorney Bonnie Dumanis, in which the person who signed it asks that she "investigate allegations that Francine Busby has encouraged illegal immigrants to participate in her campaign to the U.S. House of Representatives, and determine if there is an additional presence of illegal aliens in her campaign organization."

The letter is signed by Tony Krvaric, an officer with the San Diego County Republican Party.

The fact that someone is under investigation by a grand jury in no way implies guilt of any crime.

William Rider, 61, said he has lived in the 2400 block of Unicornio Street, the same Carlsbad street as Bilbray's mother, for the last 11 years. He showed a reporter Thursday what appeared to be a subpoena ordering him to appear before a county criminal grand jury at 1:30 p.m. Aug. 30. The paper carried the name of Patrick O'Toole, special operations division attorney.

Rider, who said he is a registered Democrat but considers himself an independent, said that after receiving the subpoena, he called O'Toole and asked if he could anticipate the summons and testify on Aug. 29, a proposal O'Toole accepted, Rider said.

Asked why he had decided to come forward just days before the Nov. 7 general election, Rider said he was doing so as a public service. He also said that he had consulted his attorney before stepping forward, and his attorney told him that he could legally talk to the media about his testimony before the grand jury.

"If they want to prosecute me for telling the truth and doing what's right, let them," Rider said.

Rider said that he supports Busby, but has not contributed money to her campaign and was not contacted by her or her staff with a request to come forward. He said he contacted them, saying that he wanted to disclose his participation in the investigation.

He said that on the day he appeared, he was taken into a room at the county courthouse on Broadway and answered questions from O'Toole and others from jurors. Rider said the questioning lasted about an hour and a half. He said that after first admonishing him not to discuss the proceedings outside of the courtroom and telling him that he was not the focus of the investigation, O'Toole said the jury was trying to determine whether somebody in his neighborhood in fact lived there.

O'Toole then proceeded to ask him a series of questions, like: "Did he know where Bilbray's mother lived? If he could see the mother's home from his house? How often he drove by Bilbray's house? If he had ever seen Bilbray helping his mother out of the house."

Rider said that O'Toole asked if he had ever seen Bilbray at the house.

"I believe I told him I had seen him there once or twice and that was eight or nine years ago," Rider said.

Contact staff writer William Finn Bennett at (760) 740-5426, or wbennett@nctimes.com.