A US federal jury convicted a former B2 stealth bomber engineer of selling military secrets and helping China design a stealth cruise missile.
Noshir Gowadia was accused of pocketing at least 110,000 US dollars from China, which he allegedly used to pay the mortgage on a multimillion-dollar oceanview home he built on Maui's north shore.
Gowadia, who has been in federal custody since October 2005, faces life in prison when he is sentenced in November.
The 66-year-old gave China a design for a cruise missile component and then showed its effectiveness when compared to United States' air-to-air missiles, according to federal prosecutors.
"This verdict sends a very clear message that no, you can't do that, and we can take care of our business here in American courtrooms when that happens," Assistant US Attorney Ken Sorenson said.
Gowadia's defence attorneys argued during the nearly four-month trial that while it is true he gave China the design for the cruise missile exhaust nozzle, he based his work on unclassified, publicly available information. Gowadia plans to appeal.
"Mr Gowadia is obviously disappointed with the verdict. He felt that he had not committed a crime," said his attorney Birney Bervar.
Gowadia was convicted on 14 of 17 counts, including conspiracy, violating the arms export control act, tax evasion and money laundering. He was acquitted on charges of knowingly communicating national defence information.
The decision came after six days of deliberations at a federal court in Honolulu.
"Mr Gowadia provided some of our country's most sensitive weapons-related designs to the Chinese government for money. Today, he is being held accountable for his actions," said Assistant Attorney General David Kris. "This prosecution should serve as a warning to others who would compromise our nation's military secrets for profit."