FBI counterintelligence agents had Maui resident Noshir Gowadia under aerial and ground surveillance for a year before they arrested him in 2005 on espionage and other charges, according to court testimony yesterday.

Gowadia, an engineer who helped develop the the U.S. Air Force's B-2 stealth bomber, is scheduled to go to trial in federal court here in April in what is believed to be the first spy trial held in Hawai'i.

Much of the evidence in the case is swathed in secrecy, and defense lawyers are disputing the legality of the FBI's use of the controversial Foreign Intelligence Security Act to conduct an emergency warrantless search of Gowadia's laptop computer at Honolulu International Airport in 2004.

Defense lawyers David Klein and Birney Bervar have asked the court to order the Justice Department to disclose applications and other paperwork related to the case that were submitted to the secret Foreign Intelligence Security Court, which oversees government compliance with FISA procedures.

In response, U.S. Attorney General Michael Mukasey filed a sworn declaration in court here last month stating that "it would harm the national security of the United States to publicly disclose or have an adversary hearing with respect to the FISA materials."

The papers, Mukasey said, "contain sensitive and classified information concerning United States intelligence sources and methods" and disclosure of the information "reasonably could be expected to cause serious damage to the national security of the United States."

Mukasey's declaration said the government was submitting the FISA materials under seal for U.S. District Judge Helen Gillmor to review privately, along with a sworn declaration from Daniel Lee Cloyd, head of the FBI's Counterintelligence Division, detailing specific facts that support the need for secrecy.

Yesterday, Gillmor began hearing arguments on that issue and other defense motions to suppress statements Gowadia made to federal investigators before he was arrested Oct. 26, 2005.

Gowadia, 68, is charged with 21 criminal counts, including charges that he helped China design and test critical components of a cruise missile.

The engineer also allegedly tried to sell military secrets to individuals in other countries, including Israel, Singapore and Germany.

Defense lawyers argue that statements Gowadia made over a two-week period to FBI agents — after his house was searched Oct. 13, 2005, but before he was formally arrested Oct. 26, 2005 — were coerced and should be suppressed.

Gowadia alleges that over the course of a dozen lengthy interviews, conducted first on Maui and later in Honolulu, FBI agents threatened to seek the death penalty against him and repeatedly threatened to arrest his wife and two adult children if he did not cooperate.

The government denied those allegations and said Gowadia volunteered to be interviewed, signed written waivers of his rights and was always free to terminate the sessions and return home, according to court papers filed by Assistant U.S. Attorney Kenneth Sorenson.

Gowadia allegedly incriminated himself in the first interview, conducted at the Maui Police Department, acknowledging that "he had been involved in disclosing classified information to the People's Republic of China."

In a later session with agents, Gowadia freely and voluntarily "described his dealings with suspected Chinese intelligence officer Tommy Wong, aka Wang Dong Ming, his entry into China, his initial work in advising China on an existing exhaust nozzle for some type of military aircraft," the government alleged.

After he allegedly admitted that he had helped the Chinese design a "stealthy cruise missile," Gowadia was asked if he understood the seriousness of what he was saying, according to prosecutors.

He then voluntarily wrote a statement that said: "On reflection what I did was wrong to help PRC make a cruise missile. What I did was espionage and treason."

FBI Special Agent James Tamura-Wageman testified at yesterday's hearing, saying he had been involved in periodic aerial and ground surveillance of Gowadia and his Maui home for a year before Gowadia's home was searched. Tamura-Wageman led the team of 15 agents who conducted a nine-hour search of Gowadia's home, seizing cartons of paper and electronic records.

The FBI agent in charge of the case, Thatcher Mohajerin, is scheduled to testify when the hearing continues today.