WALLER COUNTY, Texas -- Houston police started testing unmanned aircraft and the event was shrouded in secrecy, but it was captured on tape by Local 2 Investigates.

Neighbors in rural Waller County said they thought a top-secret military venture was under way among the farmland and ranches, some 70 miles northwest of Houston. KPRC Local 2 Investigates had four hidden cameras aimed at a row of mysterious black trucks. Satellite dishes and a swirling radar added to the neighbors' suspense.

Then, cameras were rolling as an unmanned aircraft was launched into the sky and operated by remote control.

Houston police cars were surrounding the land with a roadblock in place to check each of the dignitaries arriving for the invitation-only event. The invitation spelled out, "NO MEDIA ALLOWED."

HPD Chief Harold Hurtt attended, along with the U.S. Department of Homeland Security and dozens of officers from various police agencies in the Houston area. Few of the guests would comment as they left the test site.

News Chopper 2 had a Local 2 Investigates team following the aircraft for more than one hour as it circled overhead. Its wings spanned 10 feet and it circled at an altitude of 1,500 feet. Operators from a private firm called Insitu, Inc. manned remote controls from inside the fleet of black trucks as the guests watched a live feed from the high-powered camera aboard the 40-pound aircraft.

"I wasn't ready to publicize this," Executive Assistant Police Chief Martha Montalvo said. She and other department leaders hastily organized a news conference when they realized Local 2 Investigates had captured the entire event on camera.

"We still haven't even decided how we were going to go forward on this task, so it seemed premature to me to announce this to the media," Montalvo said. "But since, obviously, the media found out about it, then I don't see any reason why just not go forward with what we have so far."

Montalvo told reporters the unmanned aircraft would be used for "mobility" or traffic issues, evacuations during storms, homeland security, search and rescue, and also "tactical." She admitted that could include covert police actions and she said she was not ruling out someday using the drones for writing traffic tickets.

A large number of the officers at the test site were assigned to the department's ticket-writing Radar Task Force. Capt. Tom Runyan insisted they were only there to provide "site security," even though KPRC cameras spotted those officers heavily participating in the test flight.

Houston police contacted KPRC from the test site, claiming the entire airspace was restricted by the Federal Aviation Administration. Police even threatened action from the FAA if the Local 2 helicopter remained in the area. However, KPRC reported it had already checked with the FAA on numerous occasions and found no flight restrictions around the site, a point conceded by Montalvo.

HPD leaders said they would address privacy and unlawful search questions later.

South Texas College of Law professor Rocky Rhodes, who teaches the constitution and privacy issues, said, "One issue is going to be law enforcement using this and when, by using these drones, are they conducting a search in which they'd need probable cause or a warrant. If the drones are being used to get into private spaces and be able to view where the government cannot otherwise go, and to collect information that would not otherwise be able to collect, that's concerning to me."

HPD Assistant Chief Vickie King said of the unmanned aircraft, "It's interesting that privacy doesn't occur or searches aren't an issue when you have a helicopter pilot over you and it would not be used in airspace other than what our helicopters are used in already."

She admitted that police helicopters are not equipped with cameras nearly as powerful as the unmanned aircraft, but she downplayed any privacy concerns, saying news helicopters have powerful cameras as well.

HPD stressed it is working with the FAA on reviewing the technical specifications, the airworthiness and hazards of flying unmanned aircraft in an urban setting. Future test flights are planned.

The price tag for an unmanned aircraft ranges from $30,000 to $1 million each and HPD is hoping to begin law enforcement from the air by June of 2008 with these new aircraft.