LODI, Calif. — A terrorism investigation in this quiet farming town has led to the arrests of a Pakistani American and his father after the son said he trained at an al-Qaida camp in Pakistan and planned to attack U.S. hospitals and supermarkets, authorities said.

Three other Muslims from the area, including two clerics, also have been detained on immigration charges in connection with the case. Federal and local investigators are trying to determine whether the men are part of a broader network of al-Qaida supporters in the San Joaquin Valley, an agricultural area south of Sacramento, officials said.

If the allegations contained in court documents are accurate, the case provides a rare look at the unraveling of a potential terrorist plot on American soil. It also illustrates the challenges posed by Pakistan, a key ally in the war on terrorism even as it continues to serve as a breeding ground for Islamic militants.

Hamid Hayat, 22, a worker at a fruit-packing plant, and his father, Umer Hayat, 45, an ice-cream-truck driver, were arrested late Sunday and are being held on charges of making false statements to the FBI, officials said yesterday.

Immigration officials said they also had detained two Lodi imams, Mohammed Adil Khan and Shabbir Ahmed, and Khan's 19-year-old son, Mohammad Hassan Adil.

Authorities said more charges and arrests are possible. "We believe through our investigation that various individuals connected to al-Qaida have been operating in the Lodi area in various capacities," Keith Slotter, who heads the FBI's Sacramento office, told reporters at a news conference. He said the FBI had no details about specific planned terrorist acts.

Hamid Hayat, who was born in the United States, came to the FBI's attention May 29 when he was returning to the U.S. from Pakistan and authorities discovered that his name appeared on the government's "no-fly list." However, after the plane was diverted to Japan and Hayat was interviewed by the FBI, he was allowed to continue to the United States.

In California, the FBI interviewed Hayat again, and he denied any connections to terrorists or training camps, according to an FBI affidavit unsealed late Tuesday night. But after a polygraph test indicated evidence of deception, according to the affidavit, Hayat acknowledged he had spent six months in 2003 and 2004 at a camp in Pakistan that he said was "run by al-Qaida."

There he received training in weapons, explosives and hand-to-hand combat, according to information in the affidavit from FBI special agent Pedro Tenoch Aguilar. Included in the training, he reportedly told agents, was target practice using pictures of President Bush.

The affidavit also says that Hayat "specifically requested to come to the United States to carry out his jihadi mission. Potential targets for attack would include hospitals and large food stores."

Hayat's father also initially denied any connection to terrorism, but after being confronted with a videotape of his son's account he acknowledged that he had toured several militant camps in Pakistan and that he paid airfare and expenses for his son's training at one of them, according to the affidavit.

Umer Hayat has run into trouble with federal authorities before: Customs and Border Protection officials seized $27,000 he did not declare as he prepared to board a flight in the U.S. several years ago, an agency official said.

Arraigned before a U.S. magistrate Tuesday, Umer Hayat was ordered held without bail. Hamid Hayat faces arraignment tomorrow.

Johnny Griffin III, an attorney for Umer Hayat, said the relatively minor nature of the charges does not justify the amount of attention the government is giving the case.

"He is being portrayed as a terrorist, when all he has been charged with is making false statements to federal officials," Griffin said.

The government's record on terrorism arrests has not been without mistakes. After the Madrid, Spain, train bombings in March 2004, for example, FBI fingerprint experts erroneously identified a Portland attorney as a suspect. Spanish police had questioned the accuracy of the fingerprint match. A federal judge in Portland later dismissed the case and agents apologized to the attorney, Brandon Mayfield, a Muslim convert.

In another case, in Detroit, federal officials announced charges against three North African men with great fanfare in 2001. After the government initially won convictions, the cases fell apart and eventually were dismissed.

Officials cautioned that the FBI has not confirmed many aspects of the Hayats' accounts, including details about the camp.

Slotter disclosed that the younger Hayat, who was born in the United States but studied for years at his grandfather's religious school in Pakistan, has been "under investigation for an extended period of time."

An FBI official in Washington confirmed that the arrests were part of a broader investigation into suspected Islamic militants within the Pakistani community in the United States, including Lodi. He said he could not discuss details of the probe or its findings to date, given the sensitivity of U.S.-Pakistani counter-terrorism efforts.

Compiled from The Washington Post,

the Los Angeles Times and

The Associated Press

Attorney for Umer Hayat