HONOLULU — A civilian defense contractor who works in intelligence at the US Pacific Command has been charged with giving national security secrets to a 27-year-old Chinese woman he was dating, according to a criminal complaint unsealed Monday.

Benjamin Pierce Bishop, 59, is accused of sending the woman an email last May with information on existing war plans, nuclear weapons and US relations with international partners, according to the complaint filed in US District Court in Honolulu.

The complaint alleged Bishop told the woman over the telephone in September about the deployment of US strategic nuclear systems and about the ability of the US to detect other nations’ low- and medium-range ballistic missiles.

Bishop met the woman at a conference in Hawaii on international military defense issues, the complaint said. It did not specify when the conference was held, but it alleged the two began an intimate, romantic relationship in June 2011.

The complaint said the woman was living in the US as a student on a J-1 visa, for people in work- and study-based exchange programs. It was not clear what institution she attended, or where she is now.

It’s also not known which defense contractor employs Bishop.

US Attorney Florence Nakakuni didn’t answer any questions at a press briefing held to announce the charges.

Bishop allegedly hid his relationship with the woman from the government even though his position and security clearance requires him to report contact with foreign nationals.

Authorities conducting a covert search of Bishop’s home in Kapolei, a suburb about 22 miles west of downtown Honolulu, in November found 12 individual documents marked “secret” even though he’s not authorized to keep classified papers at home, the complaint said.

Last month, the woman asked Bishop what western countries knew about “the operation of a particular naval asset of People’s Republic of China,” the complaint said, though the topic fell outside Bishop’s regular work assignments. Bishop researched the issued using open source records and was observed collecting and reviewing classified information on the topic, the complaint said.

Authorities arrested Bishop at US Pacific Command headquarters at Camp H.M. Smith in Hawaii on Friday.

Bishop wore a white jail jumpsuit and was shackled by his wrists and ankles when he appeared Monday in federal court in Honolulu.

He read and signed documents with the help of a pair of black-rimmed reading glasses. He had white and gray hair and sported a few days of beard growth.

US Magistrate Judge Richard Puglisi conditionally appointed Bishop an attorney after hearing arguments that his finances weren’t sufficient to cover the high costs of defending himself against an espionage charge.

Bishop faces one count of communicating national defense information to a person not entitled to receive it and one count of unlawfully retaining national defense documents and plans.

Bishop’s court-appointed attorney, Birney Bervar, said Bishop is a lieutenant colonel in the US Army Reserve.

“Col. Bishop has served this country for 29 years. He would never do anything to harm the United States,” Bervar told reporters after Bishop was formally presented with the charges.

No one answered the door Monday at the brown, two-story home listed as Bishop’s residence. The shades were drawn and no car was in the driveway. The home is in a hilly neighborhood overlooking Pearl Harbor and downtown Honolulu.

Bart DaSilva, a neighbor of Bishop’s, said Bishop was friendly when he first moved to the neighborhood about three years ago. Though he lived alone, he brought his wife — whom he said was from Thailand — and daughter to DaSilva’s home once to socialize, DaSilva said.

But as months passed, Bishop wasn’t as friendly and kept to himself, DaSilva said. “I kind of felt, ‘What did we do?'” DaSilva said. “It was almost like he switched off.”

DaSilva said he never saw Bishop with other visitors.

Bishop was scheduled to appear in court this week for a hearing on whether he will remain in detention during the case. A preliminary hearing was scheduled for April 1.