A Navy doctor was found guilty Friday of using a hidden camera to videotape Naval Academy midshipmen engaged in sex acts.

The jury of six Navy captains deliberated for six hours over two days before finding Cmdr. Kevin Ronan guilty of seven counts of conduct unbecoming an officer, three counts of illegal wiretapping and one count of obstruction of justice.

Ronan, 41, stood at attention and showed no visible reaction as the verdict was read at the Washington Navy Yard.

Navy prosecutors alleged Ronan used a camera hidden in an air purifier to tape the male midshipmen having sex with girlfriends or masturbating while they stayed in guest bedrooms at his home in Annapolis, Md. They were there as part of an academy program that places students in private homes during their free time.

Ronan testified this week that he bought the device to make sure the students didn't throw parties while he wasn't home. He said he tested it once, but later used it only to clean the air in the spare bedrooms, not for taping.

Prosecutors said Ronan began using the device for taping as early as May 2006. Two men, one a midshipman, the other a former student, found the recordings in January and turned them over to authorities.

The same military jury is now slated to consider a sentence ranging from no formal punishment to more than 27 years in the brig. Ronan also faces dismissal from the Navy.

His father, Frank Ronan, said he was "sick, devastated and blown away" by the verdict. "We did not expect this," he said.