SACRAMENTO, Calif. - Federal authorities aren't saying much about their terrorism investigation in nearby Lodi but are making two things crystal clear: Their work in the farming town has been going on for years - and it's not over yet.

They denied the implication by some members of Lodi's large Pakistani community that the probe was triggered by a rift between fundamentalist and mainstream factions.

Each side accused the other of contacting the FBI, which is in charge of the investigation. The dispute has led to a leadership struggle at the Lodi Muslim Mosque and a legal fight with a budding Islamic learning center.

"This specific investigation has been going on for several years," FBI spokesman John Cauthen said Thursday.

The FBI alleges several people committed to al-Qaida have been operating in and around the tranquil wine-growing region just south of Sacramento.

Investigators say Hamid Hayat, 22, trained with al-Qaida in Pakistan and planned to attack hospitals and supermarkets in the United States. He is scheduled to appear in federal court today for a bail hearing.

Umer Hayat, 47, said his son was drawn to jihadist training camps in his early teenage years while attending a madrassah, or religious school, in Rawalpindi, Pakistan, that was operated by Umer Hayat's father-in-law, according to an FBI affidavit.

Hayat allegedly paid for his son to attend the terrorist camp in 2003 and 2004. The affidavit says it was run by a friend of his father-in-law's.

The Hayats are charged only with lying to federal investigators.

Two Islamic religious leaders, or imams, and one leader's son also have been detained on immigration violations. Neither Cauthen nor a spokeswoman for U.S. Immigration and Customs Enforcement would reveal specifics of the alleged visa violations.

Saad Ahmad, an attorney for the three men, did not immediately return a telephone call Thursday seeking comment.

The sequence that led to the arrests and detentions began May 29, when Hamid Hayat was trying to return to the U.S. but was identified in mid-flight as being on the federal "no-fly" list. His plane was diverted to Japan, where Hayat was interviewed by the FBI and denied any connection to terrorism.

He was allowed to fly to California, but was interviewed again last weekend. He and his father were charged after he flunked a lie detector test and then admitted attending the training camp, the affidavit said.

The Hayats and the imams are on opposite sides of a struggle between Pakistani factions in and around Lodi: The Hayats are aligned with a faction supporting more traditional Islamic values; the imams with another group seeking greater cooperation and understanding from the larger community.