A Los Angeles city councilman and his wife were indicted on a total of 24 felony counts stemming from allegations he lived outside his district, prosecutors said Wednesday.

Richard Alarcon, 56, faces 18 charges of perjury, voter fraud and filing a false declaration of candidacy. His wife, Flora Montes De Oca Alarcon, is charged with six counts including perjury and voter fraud.

They both pleaded not guilty and were released on their own recognizance.

It was not immediately clear how much prison time they would face if convicted but it could be "substantial," said Jennifer Lentz Snyder, a deputy district attorney.

The 24-page indictment was unsealed Wednesday following a 15-month investigation by the district attorney's office.

Alarcon said nothing during the court hearing but later said that "the charges by the district attorney are baseless. My wife and I are innocent."

He said he did not plan to resign from the council.

"The charges are related to my residence and not my work as a councilman," Alarcon said.

He came under investigation after complaints that he did not live in a Panorama City home he used as his voting address. The Los Angeles Times reported earlier this year that neighbors had not seen him there for years.

"The foundations of this indictment is the issue of where their domicile was," said his attorney Henry Salcido. "We are absolutely convinced that we know that they are innocent. And on this one, trust us, the government made a mistake."

Salcido said the defense has not yet received a copy of the grand jury transcript.

Alarcon maintained he lived at that address until October but he and his family moved out after a homeless man broke in. He said in January that his daughter refused to sleep in the Panorama City home.

The former state senator and assemblyman currently represents an area that includes Panorama City, Pacoima and other portions of the San Fernando Valley. In January, investigators searched the Panorama City home and another about a block away in Sun Valley, a neighboring district.

Both of the homes are owned by his wife.

Last month, the councilman said six members of his staff were subpoenaed by a grand jury.

The councilman was elected to the 7th District council seat in March 2007, and later that year unsuccessfully sought to have his district's boundaries redrawn to include his wife's Sun Valley home, prosecutors said.

The indictment charged him with filing a false declaration of candidacy on Dec. 6, 2006, and Nov. 6, 2008. It alleged he fraudulently voted in elections in 2007, 2008 and 2009.

The perjury counts include allegations the councilman filed false driver's license applications.

Alarcon is due in court on Sept. 27.